std:🧵:String - Rust (original) (raw)

Struct std::string::String1.0.0 [−] [src]

pub struct String { /* fields omitted */ }

A UTF-8 encoded, growable string.

The String type is the most common string type that has ownership over the contents of the string. It has a close relationship with its borrowed counterpart, the primitive str.

You can create a String from a literal string with String::from:

let hello = String::from("Hello, world!");Run

You can append a char to a String with the push method, and append a &str with the push_str method:

let mut hello = String::from("Hello, ");

hello.push('w'); hello.push_str("orld!");Run

If you have a vector of UTF-8 bytes, you can create a String from it with the from_utf8 method:

let sparkle_heart = vec![240, 159, 146, 150];

let sparkle_heart = String::from_utf8(sparkle_heart).unwrap();

assert_eq!("💖", sparkle_heart);Run

Strings are always valid UTF-8. This has a few implications, the first of which is that if you need a non-UTF-8 string, consider OsString. It is similar, but without the UTF-8 constraint. The second implication is that you cannot index into a String:

ⓘThis example deliberately fails to compile

let s = "hello";

println!("The first letter of s is {}", s[0]); Run

Indexing is intended to be a constant-time operation, but UTF-8 encoding does not allow us to do this. Furthermore, it's not clear what sort of thing the index should return: a byte, a codepoint, or a grapheme cluster. The bytes and chars methods return iterators over the first two, respectively.

Strings implement Deref<Target=str>, and so inherit all of str's methods. In addition, this means that you can pass a String to a function which takes a &str by using an ampersand (&):

fn takes_str(s: &str) { }

let s = String::from("Hello");

takes_str(&s);Run

This will create a &str from the String and pass it in. This conversion is very inexpensive, and so generally, functions will accept&strs as arguments unless they need a String for some specific reason.

In certain cases Rust doesn't have enough information to make this conversion, known as Deref coercion. In the following example a string slice &'a str implements the trait TraitExample, and the functionexample_func takes anything that implements the trait. In this case Rust would need to make two implicit conversions, which Rust doesn't have the means to do. For that reason, the following example will not compile.

ⓘThis example deliberately fails to compile

trait TraitExample {}

impl<'a> TraitExample for &'a str {}

fn example_func<A: TraitExample>(example_arg: A) {}

fn main() { let example_string = String::from("example_string"); example_func(&example_string); }Run

There are two options that would work instead. The first would be to change the line example_func(&example_string); toexample_func(example_string.as_str());, using the method as_str()to explicitly extract the string slice containing the string. The second way changes example_func(&example_string); toexample_func(&*example_string);. In this case we are dereferencing aString to a str, then referencing the str back to&str. The second way is more idiomatic, however both work to do the conversion explicitly rather than relying on the implicit conversion.

A String is made up of three components: a pointer to some bytes, a length, and a capacity. The pointer points to an internal buffer Stringuses to store its data. The length is the number of bytes currently stored in the buffer, and the capacity is the size of the buffer in bytes. As such, the length will always be less than or equal to the capacity.

This buffer is always stored on the heap.

You can look at these with the as_ptr, len, and capacitymethods:

use std::mem;

let story = String::from("Once upon a time...");

let ptr = story.as_ptr(); let len = story.len(); let capacity = story.capacity();

assert_eq!(19, len);

mem::forget(story);

let s = unsafe { String::from_raw_parts(ptr as *mut _, len, capacity) } ;

assert_eq!(String::from("Once upon a time..."), s);Run

If a String has enough capacity, adding elements to it will not re-allocate. For example, consider this program:

let mut s = String::new();

println!("{}", s.capacity());

for _ in 0..5 { s.push_str("hello"); println!("{}", s.capacity()); }Run

This will output the following:

0
5
10
20
20
40

At first, we have no memory allocated at all, but as we append to the string, it increases its capacity appropriately. If we instead use thewith_capacity method to allocate the correct capacity initially:

let mut s = String::with_capacity(25);

println!("{}", s.capacity());

for _ in 0..5 { s.push_str("hello"); println!("{}", s.capacity()); }Run

We end up with a different output:

25
25
25
25
25
25

Here, there's no need to allocate more memory inside the loop.

impl [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

pub fn [new](#method.new)() -> [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

Creates a new empty String.

Given that the String is empty, this will not allocate any initial buffer. While that means that this initial operation is very inexpensive, but may cause excessive allocation later, when you add data. If you have an idea of how much data the String will hold, consider the with_capacity method to prevent excessive re-allocation.

Basic usage:

let s = String::new();Run

pub fn [with_capacity](#method.with%5Fcapacity)(capacity: [usize](../primitive.usize.html)) -> [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

Creates a new empty String with a particular capacity.

Strings have an internal buffer to hold their data. The capacity is the length of that buffer, and can be queried with the capacitymethod. This method creates an empty String, but one with an initial buffer that can hold capacity bytes. This is useful when you may be appending a bunch of data to the String, reducing the number of reallocations it needs to do.

If the given capacity is 0, no allocation will occur, and this method is identical to the new method.

Basic usage:

let mut s = String::with_capacity(10);

assert_eq!(s.len(), 0);

let cap = s.capacity(); for i in 0..10 { s.push('a'); }

assert_eq!(s.capacity(), cap);

s.push('a');Run

pub fn [from_utf8](#method.from%5Futf8)(vec: [Vec](../../std/vec/struct.Vec.html "struct std::vec::Vec")<[u8](../primitive.u8.html)>) -> [Result](../../std/result/enum.Result.html "enum std::result::Result")<[String](../../std/string/struct.String.html "struct std:🧵:String"), [FromUtf8Error](../../std/string/struct.FromUtf8Error.html "struct std:🧵:FromUtf8Error")>[src]

Converts a vector of bytes to a String.

A string slice (&str) is made of bytes (u8), and a vector of bytes (Vec) is made of bytes, so this function converts between the two. Not all byte slices are valid Strings, however: Stringrequires that it is valid UTF-8. from_utf8() checks to ensure that the bytes are valid UTF-8, and then does the conversion.

If you are sure that the byte slice is valid UTF-8, and you don't want to incur the overhead of the validity check, there is an unsafe version of this function, from_utf8_unchecked, which has the same behavior but skips the check.

This method will take care to not copy the vector, for efficiency's sake.

If you need a &str instead of a String, considerstr::from_utf8.

The inverse of this method is as_bytes.

Returns Err if the slice is not UTF-8 with a description as to why the provided bytes are not UTF-8. The vector you moved in is also included.

Basic usage:

let sparkle_heart = vec![240, 159, 146, 150];

let sparkle_heart = String::from_utf8(sparkle_heart).unwrap();

assert_eq!("💖", sparkle_heart);Run

Incorrect bytes:

let sparkle_heart = vec![0, 159, 146, 150];

assert!(String::from_utf8(sparkle_heart).is_err());Run

See the docs for FromUtf8Error for more details on what you can do with this error.

pub fn [from_utf8_lossy](#method.from%5Futf8%5Flossy)(v: [&'a [](../primitive.slice.html)[u8](../primitive.u8.html)[]](../primitive.slice.html)) -> [Cow](../../std/borrow/enum.Cow.html "enum std::borrow::Cow")<'a, [str](../primitive.str.html)>[src]

Converts a slice of bytes to a string, including invalid characters.

Strings are made of bytes (u8), and a slice of bytes (&[u8]) is made of bytes, so this function converts between the two. Not all byte slices are valid strings, however: strings are required to be valid UTF-8. During this conversion,from_utf8_lossy() will replace any invalid UTF-8 sequences withU+FFFD REPLACEMENT CHARACTER, which looks like this: �

If you are sure that the byte slice is valid UTF-8, and you don't want to incur the overhead of the conversion, there is an unsafe version of this function, from_utf8_unchecked, which has the same behavior but skips the checks.

This function returns a Cow<'a, str>. If our byte slice is invalid UTF-8, then we need to insert the replacement characters, which will change the size of the string, and hence, require a String. But if it's already valid UTF-8, we don't need a new allocation. This return type allows us to handle both cases.

Basic usage:

let sparkle_heart = vec![240, 159, 146, 150];

let sparkle_heart = String::from_utf8_lossy(&sparkle_heart);

assert_eq!("💖", sparkle_heart);Run

Incorrect bytes:

let input = b"Hello \xF0\x90\x80World"; let output = String::from_utf8_lossy(input);

assert_eq!("Hello �World", output);Run

pub fn [from_utf16](#method.from%5Futf16)(v: [&[](../primitive.slice.html)[u16](../primitive.u16.html)[]](../primitive.slice.html)) -> [Result](../../std/result/enum.Result.html "enum std::result::Result")<[String](../../std/string/struct.String.html "struct std:🧵:String"), [FromUtf16Error](../../std/string/struct.FromUtf16Error.html "struct std:🧵:FromUtf16Error")>[src]

Decode a UTF-16 encoded vector v into a String, returning Errif v contains any invalid data.

Basic usage:

let v = &[0xD834, 0xDD1E, 0x006d, 0x0075, 0x0073, 0x0069, 0x0063]; assert_eq!(String::from("𝄞music"), String::from_utf16(v).unwrap());

let v = &[0xD834, 0xDD1E, 0x006d, 0x0075, 0xD800, 0x0069, 0x0063]; assert!(String::from_utf16(v).is_err());Run

pub fn [from_utf16_lossy](#method.from%5Futf16%5Flossy)(v: [&[](../primitive.slice.html)[u16](../primitive.u16.html)[]](../primitive.slice.html)) -> [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

Decode a UTF-16 encoded slice v into a String, replacing invalid data with the replacement character (U+FFFD).

Unlike from_utf8_lossy which returns a Cow<'a, str>,from_utf16_lossy returns a String since the UTF-16 to UTF-8 conversion requires a memory allocation.

Basic usage:

let v = &[0xD834, 0xDD1E, 0x006d, 0x0075, 0x0073, 0xDD1E, 0x0069, 0x0063, 0xD834];

assert_eq!(String::from("𝄞mus\u{FFFD}ic\u{FFFD}"), String::from_utf16_lossy(v));Run

`pub unsafe fn from_raw_parts(

buf: *mut u8,
length: usize,
capacity: usize
) -> String`[src]

Creates a new String from a length, capacity, and pointer.

This is highly unsafe, due to the number of invariants that aren't checked:

• The memory at ptr needs to have been previously allocated by the same allocator the standard library uses.
• length needs to be less than or equal to capacity.
• capacity needs to be the correct value.

Violating these may cause problems like corrupting the allocator's internal data structures.

The ownership of ptr is effectively transferred to theString which may then deallocate, reallocate or change the contents of memory pointed to by the pointer at will. Ensure that nothing else uses the pointer after calling this function.

Basic usage:

use std::mem;

unsafe { let s = String::from("hello"); let ptr = s.as_ptr(); let len = s.len(); let capacity = s.capacity();

mem::forget(s);

let s = String::from_raw_parts(ptr as *mut _, len, capacity);

assert_eq!(String::from("hello"), s);

}Run

pub unsafe fn [from_utf8_unchecked](#method.from%5Futf8%5Funchecked)(bytes: [Vec](../../std/vec/struct.Vec.html "struct std::vec::Vec")<[u8](../primitive.u8.html)>) -> [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

Converts a vector of bytes to a String without checking that the string contains valid UTF-8.

See the safe version, from_utf8, for more details.

This function is unsafe because it does not check that the bytes passed to it are valid UTF-8. If this constraint is violated, it may cause memory unsafety issues with future users of the String, as the rest of the standard library assumes that Strings are valid UTF-8.

Basic usage:

let sparkle_heart = vec![240, 159, 146, 150];

let sparkle_heart = unsafe { String::from_utf8_unchecked(sparkle_heart) };

assert_eq!("💖", sparkle_heart);Run

ⓘImportant traits for Vec<u8>

pub fn [into_bytes](#method.into%5Fbytes)(self) -> [Vec](../../std/vec/struct.Vec.html "struct std::vec::Vec")<[u8](../primitive.u8.html)>[src]

Converts a String into a byte vector.

This consumes the String, so we do not need to copy its contents.

Basic usage:

let s = String::from("hello"); let bytes = s.into_bytes();

assert_eq!(&[104, 101, 108, 108, 111][..], &bytes[..]);Run

pub fn [as_str](#method.as%5Fstr)(&self) -> &[str](../primitive.str.html)

1.7.0

[src]

Extracts a string slice containing the entire string.

Basic usage:

let s = String::from("foo");

assert_eq!("foo", s.as_str());Run

pub fn [as_mut_str](#method.as%5Fmut%5Fstr)(&mut self) -> &mut [str](../primitive.str.html)

1.7.0

[src]

Converts a String into a mutable string slice.

Basic usage:

let mut s = String::from("foobar"); let s_mut_str = s.as_mut_str();

s_mut_str.make_ascii_uppercase();

assert_eq!("FOOBAR", s_mut_str);Run

pub fn [push_str](#method.push%5Fstr)(&mut self, string: &[str](../primitive.str.html))[src]

Appends a given string slice onto the end of this String.

Basic usage:

let mut s = String::from("foo");

s.push_str("bar");

assert_eq!("foobar", s);Run

pub fn [capacity](#method.capacity)(&self) -> [usize](../primitive.usize.html)[src]

Returns this String's capacity, in bytes.

Basic usage:

let s = String::with_capacity(10);

assert!(s.capacity() >= 10);Run

pub fn [reserve](#method.reserve)(&mut self, additional: [usize](../primitive.usize.html))[src]

Ensures that this String's capacity is at least additional bytes larger than its length.

The capacity may be increased by more than additional bytes if it chooses, to prevent frequent reallocations.

If you do not want this "at least" behavior, see the reserve_exactmethod.

Panics if the new capacity overflows usize.

Basic usage:

let mut s = String::new();

s.reserve(10);

assert!(s.capacity() >= 10);Run

This may not actually increase the capacity:

let mut s = String::with_capacity(10); s.push('a'); s.push('b');

assert_eq!(2, s.len()); assert_eq!(10, s.capacity());

s.reserve(8);

assert_eq!(10, s.capacity());Run

pub fn [reserve_exact](#method.reserve%5Fexact)(&mut self, additional: [usize](../primitive.usize.html))[src]

Ensures that this String's capacity is additional bytes larger than its length.

Consider using the reserve method unless you absolutely know better than the allocator.

Panics if the new capacity overflows usize.

Basic usage:

let mut s = String::new();

s.reserve_exact(10);

assert!(s.capacity() >= 10);Run

This may not actually increase the capacity:

let mut s = String::with_capacity(10); s.push('a'); s.push('b');

assert_eq!(2, s.len()); assert_eq!(10, s.capacity());

s.reserve_exact(8);

assert_eq!(10, s.capacity());Run

pub fn [shrink_to_fit](#method.shrink%5Fto%5Ffit)(&mut self)[src]

Shrinks the capacity of this String to match its length.

Basic usage:

let mut s = String::from("foo");

s.reserve(100); assert!(s.capacity() >= 100);

s.shrink_to_fit(); assert_eq!(3, s.capacity());Run

pub fn [push](#method.push)(&mut self, ch: [char](../primitive.char.html))[src]

Appends the given char to the end of this String.

Basic usage:

let mut s = String::from("abc");

s.push('1'); s.push('2'); s.push('3');

assert_eq!("abc123", s);Run

pub fn [as_bytes](#method.as%5Fbytes)(&self) -> [&[](../primitive.slice.html)[u8](../primitive.u8.html)[]](../primitive.slice.html)[src]

Returns a byte slice of this String's contents.

The inverse of this method is from_utf8.

Basic usage:

let s = String::from("hello");

assert_eq!(&[104, 101, 108, 108, 111], s.as_bytes());Run

pub fn [truncate](#method.truncate)(&mut self, new_len: [usize](../primitive.usize.html))[src]

Shortens this String to the specified length.

If new_len is greater than the string's current length, this has no effect.

Note that this method has no effect on the allocated capacity of the string

Panics if new_len does not lie on a char boundary.

Basic usage:

let mut s = String::from("hello");

s.truncate(2);

assert_eq!("he", s);Run

pub fn [pop](#method.pop)(&mut self) -> [Option](../../std/option/enum.Option.html "enum std::option::Option")<[char](../primitive.char.html)>[src]

Removes the last character from the string buffer and returns it.

Returns None if this String is empty.

Basic usage:

let mut s = String::from("foo");

assert_eq!(s.pop(), Some('o')); assert_eq!(s.pop(), Some('o')); assert_eq!(s.pop(), Some('f'));

assert_eq!(s.pop(), None);Run

pub fn [remove](#method.remove)(&mut self, idx: [usize](../primitive.usize.html)) -> [char](../primitive.char.html)[src]

Removes a char from this String at a byte position and returns it.

This is an O(n) operation, as it requires copying every element in the buffer.

Panics if idx is larger than or equal to the String's length, or if it does not lie on a char boundary.

Basic usage:

let mut s = String::from("foo");

assert_eq!(s.remove(0), 'f'); assert_eq!(s.remove(1), 'o'); assert_eq!(s.remove(0), 'o');Run

`pub fn retain(&mut self, f: F) where

F: FnMut(char) -> bool, `[src]

🔬 This is a nightly-only experimental API. (string_retain #43874)

Retains only the characters specified by the predicate.

In other words, remove all characters c such that f(c) returns false. This method operates in place and preserves the order of the retained characters.

#![feature(string_retain)]

let mut s = String::from("f_o_ob_ar");

s.retain(|c| c != '_');

assert_eq!(s, "foobar");Run

pub fn [insert](#method.insert)(&mut self, idx: [usize](../primitive.usize.html), ch: [char](../primitive.char.html))[src]

Inserts a character into this String at a byte position.

This is an O(n) operation as it requires copying every element in the buffer.

Panics if idx is larger than the String's length, or if it does not lie on a char boundary.

Basic usage:

let mut s = String::with_capacity(3);

s.insert(0, 'f'); s.insert(1, 'o'); s.insert(2, 'o');

assert_eq!("foo", s);Run

pub fn [insert_str](#method.insert%5Fstr)(&mut self, idx: [usize](../primitive.usize.html), string: &[str](../primitive.str.html))

1.16.0

[src]

Inserts a string slice into this String at a byte position.

This is an O(n) operation as it requires copying every element in the buffer.

Panics if idx is larger than the String's length, or if it does not lie on a char boundary.

Basic usage:

let mut s = String::from("bar");

s.insert_str(0, "foo");

assert_eq!("foobar", s);Run

ⓘImportant traits for Vec<u8>

pub unsafe fn [as_mut_vec](#method.as%5Fmut%5Fvec)(&mut self) -> &mut [Vec](../../std/vec/struct.Vec.html "struct std::vec::Vec")<[u8](../primitive.u8.html)>[src]

Returns a mutable reference to the contents of this String.

This function is unsafe because it does not check that the bytes passed to it are valid UTF-8. If this constraint is violated, it may cause memory unsafety issues with future users of the String, as the rest of the standard library assumes that Strings are valid UTF-8.

Basic usage:

let mut s = String::from("hello");

unsafe { let vec = s.as_mut_vec(); assert_eq!(&[104, 101, 108, 108, 111][..], &vec[..]);

vec.reverse();

} assert_eq!(s, "olleh");Run

pub fn [len](#method.len)(&self) -> [usize](../primitive.usize.html)[src]

Returns the length of this String, in bytes.

Basic usage:

let a = String::from("foo");

assert_eq!(a.len(), 3);Run

pub fn [is_empty](#method.is%5Fempty)(&self) -> [bool](../primitive.bool.html)[src]

Returns true if this String has a length of zero.

Returns false otherwise.

Basic usage:

let mut v = String::new(); assert!(v.is_empty());

v.push('a'); assert!(!v.is_empty());Run

pub fn [split_off](#method.split%5Foff)(&mut self, at: [usize](../primitive.usize.html)) -> [String](../../std/string/struct.String.html "struct std:🧵:String")

1.16.0

[src]

Splits the string into two at the given index.

Returns a newly allocated String. self contains bytes [0, at), and the returned String contains bytes [at, len). at must be on the boundary of a UTF-8 code point.

Note that the capacity of self does not change.

Panics if at is not on a UTF-8 code point boundary, or if it is beyond the last code point of the string.

let mut hello = String::from("Hello, World!"); let world = hello.split_off(7); assert_eq!(hello, "Hello, "); assert_eq!(world, "World!");Run

pub fn [clear](#method.clear)(&mut self)[src]

Truncates this String, removing all contents.

While this means the String will have a length of zero, it does not touch its capacity.

Basic usage:

let mut s = String::from("foo");

s.clear();

assert!(s.is_empty()); assert_eq!(0, s.len()); assert_eq!(3, s.capacity());Run

ⓘImportant traits for Drain<'a>

pub fn [drain](#method.drain)<R>(&mut self, range: R) -> [Drain](../../std/string/struct.Drain.html "struct std:🧵:Drain") where R: [RangeArgument](../../std/collections/range/trait.RangeArgument.html "trait std::collections::range::RangeArgument")<[usize](../primitive.usize.html)>,

1.6.0

[src]

Creates a draining iterator that removes the specified range in the string and yields the removed chars.

Note: The element range is removed even if the iterator is not consumed until the end.

Panics if the starting point or end point do not lie on a charboundary, or if they're out of bounds.

Basic usage:

let mut s = String::from("α is alpha, β is beta"); let beta_offset = s.find('β').unwrap_or(s.len());

let t: String = s.drain(..beta_offset).collect(); assert_eq!(t, "α is alpha, "); assert_eq!(s, "β is beta");

s.drain(..); assert_eq!(s, "");Run

`pub fn splice(&mut self, range: R, replace_with: &str) where

R: RangeArgument<usize>, `[src]

🔬 This is a nightly-only experimental API. (splice #44643)

recently added

Creates a splicing iterator that removes the specified range in the string, and replaces it with the given string. The given string doesn't need to be the same length as the range.

Note: Unlike Vec::splice, the replacement happens eagerly, and this method does not return the removed chars.

Panics if the starting point or end point do not lie on a charboundary, or if they're out of bounds.

Basic usage:

#![feature(splice)] let mut s = String::from("α is alpha, β is beta"); let beta_offset = s.find('β').unwrap_or(s.len());

s.splice(..beta_offset, "Α is capital alpha; "); assert_eq!(s, "Α is capital alpha; β is beta");Run

ⓘImportant traits for Box

pub fn [into_boxed_str](#method.into%5Fboxed%5Fstr)(self) -> [Box](../../std/boxed/struct.Box.html "struct std::boxed::Box")<[str](../primitive.str.html)>

1.4.0

[src]

Converts this String into a Box<str>.

This will drop any excess capacity.

Basic usage:

let s = String::from("hello");

let b = s.into_boxed_str();Run

pub fn [len](#method.len-1)(&self) -> [usize](../primitive.usize.html)[src]

Returns the length of self.

This length is in bytes, not chars or graphemes. In other words, it may not be what a human considers the length of the string.

Basic usage:

let len = "foo".len(); assert_eq!(3, len);

let len = "ƒoo".len(); assert_eq!(4, len);Run

pub fn [is_empty](#method.is%5Fempty-1)(&self) -> [bool](../primitive.bool.html)[src]

Returns true if self has a length of zero bytes.

Basic usage:

let s = ""; assert!(s.is_empty());

let s = "not empty"; assert!(!s.is_empty());Run

pub fn [is_char_boundary](#method.is%5Fchar%5Fboundary)(&self, index: [usize](../primitive.usize.html)) -> [bool](../primitive.bool.html)

1.9.0

[src]

Checks that index-th byte lies at the start and/or end of a UTF-8 code point sequence.

The start and end of the string (when index == self.len()) are considered to be boundaries.

Returns false if index is greater than self.len().

let s = "Löwe 老虎 Léopard"; assert!(s.is_char_boundary(0));

assert!(s.is_char_boundary(6)); assert!(s.is_char_boundary(s.len()));

assert!(!s.is_char_boundary(2));

assert!(!s.is_char_boundary(8));Run

pub fn [as_bytes](#method.as%5Fbytes-1)(&self) -> [&[](../primitive.slice.html)[u8](../primitive.u8.html)[]](../primitive.slice.html)[src]

Converts a string slice to a byte slice. To convert the byte slice back into a string slice, use the str::from_utf8 function.

Basic usage:

let bytes = "bors".as_bytes(); assert_eq!(b"bors", bytes);Run

pub unsafe fn [as_bytes_mut](#method.as%5Fbytes%5Fmut)(&mut self) -> [&mut [](../primitive.slice.html)[u8](../primitive.u8.html)[]](../primitive.slice.html)

1.20.0

[src]

Converts a mutable string slice to a mutable byte slice. To convert the mutable byte slice back into a mutable string slice, use thestr::from_utf8_mut function.

Basic usage:

let mut s = String::from("Hello"); let bytes = unsafe { s.as_bytes_mut() };

assert_eq!(b"Hello", bytes);Run

Mutability:

let mut s = String::from("🗻∈🌏");

unsafe { let bytes = s.as_bytes_mut();

bytes[0] = 0xF0;
bytes[1] = 0x9F;
bytes[2] = 0x8D;
bytes[3] = 0x94;

}

assert_eq!("🍔∈🌏", s);Run

pub fn [as_ptr](#method.as%5Fptr)(&self) -> [*const ](../primitive.pointer.html)[u8](../primitive.u8.html)[src]

Converts a string slice to a raw pointer.

As string slices are a slice of bytes, the raw pointer points to au8. This pointer will be pointing to the first byte of the string slice.

Basic usage:

let s = "Hello"; let ptr = s.as_ptr();Run

`pub fn get(&self, i: I) -> Option<&<I as SliceIndex<str>>::Output> where

I: SliceIndex<str>, `

1.20.0

[src]

Returns a subslice of str.

This is the non-panicking alternative to indexing the str. ReturnsNone whenever equivalent indexing operation would panic.

let v = String::from("🗻∈🌏");

assert_eq!(Some("🗻"), v.get(0..4));

assert!(v.get(1..).is_none()); assert!(v.get(..8).is_none());

assert!(v.get(..42).is_none());Run

`pub fn get_mut(

&mut self,
i: I
) -> Option<&mut <I as SliceIndex<str>>::Output> where
I: SliceIndex<str>, `

1.20.0

[src]

Returns a mutable subslice of str.

This is the non-panicking alternative to indexing the str. ReturnsNone whenever equivalent indexing operation would panic.

let mut v = String::from("hello");

assert!(v.get_mut(0..5).is_some());

assert!(v.get_mut(..42).is_none()); assert_eq!(Some("he"), v.get_mut(0..2).map(|v| &*v));

assert_eq!("hello", v); { let s = v.get_mut(0..2); let s = s.map(|s| { s.make_ascii_uppercase(); &*s }); assert_eq!(Some("HE"), s); } assert_eq!("HEllo", v);Run

`pub unsafe fn get_unchecked(&self, i: I) -> &<I as SliceIndex<str>>::Output where

I: SliceIndex<str>, `

1.20.0

[src]

Returns a unchecked subslice of str.

This is the unchecked alternative to indexing the str.

Callers of this function are responsible that these preconditions are satisfied:

• The starting index must come before the ending index;
• Indexes must be within bounds of the original slice;
• Indexes must lie on UTF-8 sequence boundaries.

Failing that, the returned string slice may reference invalid memory or violate the invariants communicated by the str type.

let v = "🗻∈🌏"; unsafe { assert_eq!("🗻", v.get_unchecked(0..4)); assert_eq!("∈", v.get_unchecked(4..7)); assert_eq!("🌏", v.get_unchecked(7..11)); }Run

`pub unsafe fn get_unchecked_mut(

&mut self,
i: I
) -> &mut <I as SliceIndex<str>>::Output where
I: SliceIndex<str>, `

1.20.0

[src]

Returns a mutable, unchecked subslice of str.

This is the unchecked alternative to indexing the str.

Callers of this function are responsible that these preconditions are satisfied:

• The starting index must come before the ending index;
• Indexes must be within bounds of the original slice;
• Indexes must lie on UTF-8 sequence boundaries.

Failing that, the returned string slice may reference invalid memory or violate the invariants communicated by the str type.

let mut v = String::from("🗻∈🌏"); unsafe { assert_eq!("🗻", v.get_unchecked_mut(0..4)); assert_eq!("∈", v.get_unchecked_mut(4..7)); assert_eq!("🌏", v.get_unchecked_mut(7..11)); }Run

pub unsafe fn [slice_unchecked](#method.slice%5Funchecked)(&self, begin: [usize](../primitive.usize.html), end: [usize](../primitive.usize.html)) -> &[str](../primitive.str.html)[src]

Creates a string slice from another string slice, bypassing safety checks.

This is generally not recommended, use with caution! For a safe alternative see str and Index.

This new slice goes from begin to end, including begin but excluding end.

To get a mutable string slice instead, see theslice_mut_unchecked method.

Callers of this function are responsible that three preconditions are satisfied:

• begin must come before end.
• begin and end must be byte positions within the string slice.
• begin and end must lie on UTF-8 sequence boundaries.

Basic usage:

let s = "Löwe 老虎 Léopard";

unsafe { assert_eq!("Löwe 老虎 Léopard", s.slice_unchecked(0, 21)); }

let s = "Hello, world!";

unsafe { assert_eq!("world", s.slice_unchecked(7, 12)); }Run

`pub unsafe fn slice_mut_unchecked(

&mut self,
begin: usize,
end: usize
) -> &mut str`

1.5.0

[src]

Creates a string slice from another string slice, bypassing safety checks. This is generally not recommended, use with caution! For a safe alternative see str and IndexMut.

This new slice goes from begin to end, including begin but excluding end.

To get an immutable string slice instead, see theslice_unchecked method.

Callers of this function are responsible that three preconditions are satisfied:

• begin must come before end.
• begin and end must be byte positions within the string slice.
• begin and end must lie on UTF-8 sequence boundaries.

pub fn [split_at](#method.split%5Fat)(&self, mid: [usize](../primitive.usize.html)) -> [(](../primitive.tuple.html)&[str](../primitive.str.html), &[str](../primitive.str.html)[)](../primitive.tuple.html)

1.4.0

[src]

Divide one string slice into two at an index.

The argument, mid, should be a byte offset from the start of the string. It must also be on the boundary of a UTF-8 code point.

The two slices returned go from the start of the string slice to mid, and from mid to the end of the string slice.

To get mutable string slices instead, see the split_at_mutmethod.

Panics if mid is not on a UTF-8 code point boundary, or if it is beyond the last code point of the string slice.

Basic usage:

let s = "Per Martin-Löf";

let (first, last) = s.split_at(3);

assert_eq!("Per", first); assert_eq!(" Martin-Löf", last);Run

pub fn [split_at_mut](#method.split%5Fat%5Fmut)(&mut self, mid: [usize](../primitive.usize.html)) -> [(](../primitive.tuple.html)&mut [str](../primitive.str.html), &mut [str](../primitive.str.html)[)](../primitive.tuple.html)

1.4.0

[src]

Divide one mutable string slice into two at an index.

The argument, mid, should be a byte offset from the start of the string. It must also be on the boundary of a UTF-8 code point.

The two slices returned go from the start of the string slice to mid, and from mid to the end of the string slice.

To get immutable string slices instead, see the split_at method.

Panics if mid is not on a UTF-8 code point boundary, or if it is beyond the last code point of the string slice.

Basic usage:

let mut s = "Per Martin-Löf".to_string(); { let (first, last) = s.split_at_mut(3); first.make_ascii_uppercase(); assert_eq!("PER", first); assert_eq!(" Martin-Löf", last); } assert_eq!("PER Martin-Löf", s);Run

ⓘImportant traits for Chars<'a>

pub fn [chars](#method.chars)(&self) -> [Chars](../../std/str/struct.Chars.html "struct std::str::Chars")[src]

Returns an iterator over the chars of a string slice.

As a string slice consists of valid UTF-8, we can iterate through a string slice by char. This method returns such an iterator.

It's important to remember that char represents a Unicode Scalar Value, and may not match your idea of what a 'character' is. Iteration over grapheme clusters may be what you actually want.

Basic usage:

let word = "goodbye";

let count = word.chars().count(); assert_eq!(7, count);

let mut chars = word.chars();

assert_eq!(Some('g'), chars.next()); assert_eq!(Some('o'), chars.next()); assert_eq!(Some('o'), chars.next()); assert_eq!(Some('d'), chars.next()); assert_eq!(Some('b'), chars.next()); assert_eq!(Some('y'), chars.next()); assert_eq!(Some('e'), chars.next());

assert_eq!(None, chars.next());Run

Remember, chars may not match your human intuition about characters:

let y = "y̆";

let mut chars = y.chars();

assert_eq!(Some('y'), chars.next()); assert_eq!(Some('\u{0306}'), chars.next());

assert_eq!(None, chars.next());Run

pub fn [char_indices](#method.char%5Findices)(&self) -> [CharIndices](../../std/str/struct.CharIndices.html "struct std::str::CharIndices")[src]

Returns an iterator over the chars of a string slice, and their positions.

As a string slice consists of valid UTF-8, we can iterate through a string slice by char. This method returns an iterator of both these chars, as well as their byte positions.

The iterator yields tuples. The position is first, the char is second.

Basic usage:

let word = "goodbye";

let count = word.char_indices().count(); assert_eq!(7, count);

let mut char_indices = word.char_indices();

assert_eq!(Some((0, 'g')), char_indices.next()); assert_eq!(Some((1, 'o')), char_indices.next()); assert_eq!(Some((2, 'o')), char_indices.next()); assert_eq!(Some((3, 'd')), char_indices.next()); assert_eq!(Some((4, 'b')), char_indices.next()); assert_eq!(Some((5, 'y')), char_indices.next()); assert_eq!(Some((6, 'e')), char_indices.next());

assert_eq!(None, char_indices.next());Run

Remember, chars may not match your human intuition about characters:

let yes = "y̆es";

let mut char_indices = yes.char_indices();

assert_eq!(Some((0, 'y')), char_indices.next()); assert_eq!(Some((1, '\u{0306}')), char_indices.next());

assert_eq!(Some((3, 'e')), char_indices.next()); assert_eq!(Some((4, 's')), char_indices.next());

assert_eq!(None, char_indices.next());Run

ⓘImportant traits for Bytes<'a>

pub fn [bytes](#method.bytes)(&self) -> [Bytes](../../std/str/struct.Bytes.html "struct std::str::Bytes")[src]

An iterator over the bytes of a string slice.

As a string slice consists of a sequence of bytes, we can iterate through a string slice by byte. This method returns such an iterator.

Basic usage:

let mut bytes = "bors".bytes();

assert_eq!(Some(b'b'), bytes.next()); assert_eq!(Some(b'o'), bytes.next()); assert_eq!(Some(b'r'), bytes.next()); assert_eq!(Some(b's'), bytes.next());

assert_eq!(None, bytes.next());Run

pub fn [split_whitespace](#method.split%5Fwhitespace)(&self) -> [SplitWhitespace](../../std/str/struct.SplitWhitespace.html "struct std::str::SplitWhitespace")

1.1.0

[src]

Split a string slice by whitespace.

The iterator returned will return string slices that are sub-slices of the original string slice, separated by any amount of whitespace.

'Whitespace' is defined according to the terms of the Unicode Derived Core Property White_Space.

Basic usage:

let mut iter = "A few words".split_whitespace();

assert_eq!(Some("A"), iter.next()); assert_eq!(Some("few"), iter.next()); assert_eq!(Some("words"), iter.next());

assert_eq!(None, iter.next());Run

All kinds of whitespace are considered:

let mut iter = " Mary had\ta\u{2009}little \n\t lamb".split_whitespace(); assert_eq!(Some("Mary"), iter.next()); assert_eq!(Some("had"), iter.next()); assert_eq!(Some("a"), iter.next()); assert_eq!(Some("little"), iter.next()); assert_eq!(Some("lamb"), iter.next());

assert_eq!(None, iter.next());Run

ⓘImportant traits for Lines<'a>

pub fn [lines](#method.lines)(&self) -> [Lines](../../std/str/struct.Lines.html "struct std::str::Lines")[src]

An iterator over the lines of a string, as string slices.

Lines are ended with either a newline (\n) or a carriage return with a line feed (\r\n).

The final line ending is optional.

Basic usage:

let text = "foo\r\nbar\n\nbaz\n"; let mut lines = text.lines();

assert_eq!(Some("foo"), lines.next()); assert_eq!(Some("bar"), lines.next()); assert_eq!(Some(""), lines.next()); assert_eq!(Some("baz"), lines.next());

assert_eq!(None, lines.next());Run

The final line ending isn't required:

let text = "foo\nbar\n\r\nbaz"; let mut lines = text.lines();

assert_eq!(Some("foo"), lines.next()); assert_eq!(Some("bar"), lines.next()); assert_eq!(Some(""), lines.next()); assert_eq!(Some("baz"), lines.next());

assert_eq!(None, lines.next());Run

pub fn [lines_any](#method.lines%5Fany)(&self) -> [LinesAny](../../std/str/struct.LinesAny.html "struct std::str::LinesAny")[src]

Deprecated since 1.4.0

: use lines() instead now

An iterator over the lines of a string.

pub fn [encode_utf16](#method.encode%5Futf16)(&self) -> [EncodeUtf16](../../std/str/struct.EncodeUtf16.html "struct std::str::EncodeUtf16")

1.8.0

[src]

Returns an iterator of u16 over the string encoded as UTF-16.

Basic usage:

let text = "Zażółć gęślą jaźń";

let utf8_len = text.len(); let utf16_len = text.encode_utf16().count();

assert!(utf16_len <= utf8_len);Run

`pub fn contains<'a, P>(&'a self, pat: P) -> bool where

P: Pattern<'a>, `[src]

Returns true if the given pattern matches a sub-slice of this string slice.

Returns false if it does not.

Basic usage:

let bananas = "bananas";

assert!(bananas.contains("nana")); assert!(!bananas.contains("apples"));Run

`pub fn starts_with<'a, P>(&'a self, pat: P) -> bool where

P: Pattern<'a>, `[src]

Returns true if the given pattern matches a prefix of this string slice.

Returns false if it does not.

Basic usage:

let bananas = "bananas";

assert!(bananas.starts_with("bana")); assert!(!bananas.starts_with("nana"));Run

`pub fn ends_with<'a, P>(&'a self, pat: P) -> bool where

P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>, `[src]

Returns true if the given pattern matches a suffix of this string slice.

Returns false if it does not.

Basic usage:

let bananas = "bananas";

assert!(bananas.ends_with("anas")); assert!(!bananas.ends_with("nana"));Run

`pub fn find<'a, P>(&'a self, pat: P) -> Option<usize> where

P: Pattern<'a>, `[src]

Returns the byte index of the first character of this string slice that matches the pattern.

Returns None if the pattern doesn't match.

The pattern can be a &str, char, or a closure that determines if a character matches.

Simple patterns:

let s = "Löwe 老虎 Léopard";

assert_eq!(s.find('L'), Some(0)); assert_eq!(s.find('é'), Some(14)); assert_eq!(s.find("Léopard"), Some(13));Run

More complex patterns using point-free style and closures:

let s = "Löwe 老虎 Léopard";

assert_eq!(s.find(char::is_whitespace), Some(5)); assert_eq!(s.find(char::is_lowercase), Some(1)); assert_eq!(s.find(|c: char| c.is_whitespace() || c.is_lowercase()), Some(1)); assert_eq!(s.find(|c: char| (c < 'o') && (c > 'a')), Some(4));Run

Not finding the pattern:

let s = "Löwe 老虎 Léopard"; let x: &[_] = &['1', '2'];

assert_eq!(s.find(x), None);Run

`pub fn rfind<'a, P>(&'a self, pat: P) -> Option<usize> where

P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>, `[src]

Returns the byte index of the last character of this string slice that matches the pattern.

Returns None if the pattern doesn't match.

The pattern can be a &str, char, or a closure that determines if a character matches.

Simple patterns:

let s = "Löwe 老虎 Léopard";

assert_eq!(s.rfind('L'), Some(13)); assert_eq!(s.rfind('é'), Some(14));Run

More complex patterns with closures:

let s = "Löwe 老虎 Léopard";

assert_eq!(s.rfind(char::is_whitespace), Some(12)); assert_eq!(s.rfind(char::is_lowercase), Some(20));Run

Not finding the pattern:

let s = "Löwe 老虎 Léopard"; let x: &[_] = &['1', '2'];

assert_eq!(s.rfind(x), None);Run

ⓘImportant traits for Split<'a, P>

pub fn [split](#method.split)<'a, P>(&'a self, pat: P) -> [Split](../../std/str/struct.Split.html "struct std::str::Split")<'a, P> where P: [Pattern](../../std/str/pattern/trait.Pattern.html "trait std::str::pattern::Pattern")<'a>, [src]

An iterator over substrings of this string slice, separated by characters matched by a pattern.

The pattern can be a &str, char, or a closure that determines the split.

The returned iterator will be a DoubleEndedIterator if the pattern allows a reverse search and forward/reverse search yields the same elements. This is true for, eg, char but not for &str.

If the pattern allows a reverse search but its results might differ from a forward search, the rsplit method can be used.

Simple patterns:

let v: Vec<&str> = "Mary had a little lamb".split(' ').collect(); assert_eq!(v, ["Mary", "had", "a", "little", "lamb"]);

let v: Vec<&str> = "".split('X').collect(); assert_eq!(v, [""]);

let v: Vec<&str> = "lionXXtigerXleopard".split('X').collect(); assert_eq!(v, ["lion", "", "tiger", "leopard"]);

let v: Vec<&str> = "lion:🐅:leopard".split("::").collect(); assert_eq!(v, ["lion", "tiger", "leopard"]);

let v: Vec<&str> = "abc1def2ghi".split(char::is_numeric).collect(); assert_eq!(v, ["abc", "def", "ghi"]);

let v: Vec<&str> = "lionXtigerXleopard".split(char::is_uppercase).collect(); assert_eq!(v, ["lion", "tiger", "leopard"]);Run

A more complex pattern, using a closure:

let v: Vec<&str> = "abc1defXghi".split(|c| c == '1' || c == 'X').collect(); assert_eq!(v, ["abc", "def", "ghi"]);Run

If a string contains multiple contiguous separators, you will end up with empty strings in the output:

let x = "||||a||b|c".to_string(); let d: Vec<_> = x.split('|').collect();

assert_eq!(d, &["", "", "", "", "a", "", "b", "c"]);Run

Contiguous separators are separated by the empty string.

let x = "(///)".to_string(); let d: Vec<_> = x.split('/').collect();

assert_eq!(d, &["(", "", "", ")"]);Run

Separators at the start or end of a string are neighbored by empty strings.

let d: Vec<_> = "010".split("0").collect(); assert_eq!(d, &["", "1", ""]);Run

When the empty string is used as a separator, it separates every character in the string, along with the beginning and end of the string.

let f: Vec<_> = "rust".split("").collect(); assert_eq!(f, &["", "r", "u", "s", "t", ""]);Run

Contiguous separators can lead to possibly surprising behavior when whitespace is used as the separator. This code is correct:

let x = " a b c".to_string(); let d: Vec<_> = x.split(' ').collect();

assert_eq!(d, &["", "", "", "", "a", "", "b", "c"]);Run

It does not give you:

ⓘThis example is not tested

assert_eq!(d, &["a", "b", "c"]);Run

Use split_whitespace for this behavior.

ⓘImportant traits for RSplit<'a, P>

pub fn [rsplit](#method.rsplit)<'a, P>(&'a self, pat: P) -> [RSplit](../../std/str/struct.RSplit.html "struct std::str::RSplit")<'a, P> where P: [Pattern](../../std/str/pattern/trait.Pattern.html "trait std::str::pattern::Pattern")<'a>, <P as [Pattern](../../std/str/pattern/trait.Pattern.html "trait std::str::pattern::Pattern")<'a>>::[Searcher](../../std/str/pattern/trait.Pattern.html#associatedtype.Searcher "type std::str::pattern::Pattern::Searcher"): [ReverseSearcher](../../std/str/pattern/trait.ReverseSearcher.html "trait std::str::pattern::ReverseSearcher")<'a>, [src]

An iterator over substrings of the given string slice, separated by characters matched by a pattern and yielded in reverse order.

The pattern can be a &str, char, or a closure that determines the split.

The returned iterator requires that the pattern supports a reverse search, and it will be a DoubleEndedIterator if a forward/reverse search yields the same elements.

For iterating from the front, the split method can be used.

Simple patterns:

let v: Vec<&str> = "Mary had a little lamb".rsplit(' ').collect(); assert_eq!(v, ["lamb", "little", "a", "had", "Mary"]);

let v: Vec<&str> = "".rsplit('X').collect(); assert_eq!(v, [""]);

let v: Vec<&str> = "lionXXtigerXleopard".rsplit('X').collect(); assert_eq!(v, ["leopard", "tiger", "", "lion"]);

let v: Vec<&str> = "lion:🐅:leopard".rsplit("::").collect(); assert_eq!(v, ["leopard", "tiger", "lion"]);Run

A more complex pattern, using a closure:

let v: Vec<&str> = "abc1defXghi".rsplit(|c| c == '1' || c == 'X').collect(); assert_eq!(v, ["ghi", "def", "abc"]);Run

`pub fn split_terminator<'a, P>(&'a self, pat: P) -> SplitTerminator<'a, P> where

P: Pattern<'a>, `[src]

An iterator over substrings of the given string slice, separated by characters matched by a pattern.

The pattern can be a &str, char, or a closure that determines the split.

Equivalent to split, except that the trailing substring is skipped if empty.

This method can be used for string data that is terminated, rather than separated by a pattern.

The returned iterator will be a DoubleEndedIterator if the pattern allows a reverse search and forward/reverse search yields the same elements. This is true for, eg, char but not for &str.

If the pattern allows a reverse search but its results might differ from a forward search, the rsplit_terminator method can be used.

Basic usage:

let v: Vec<&str> = "A.B.".split_terminator('.').collect(); assert_eq!(v, ["A", "B"]);

let v: Vec<&str> = "A..B..".split_terminator(".").collect(); assert_eq!(v, ["A", "", "B", ""]);Run

`pub fn rsplit_terminator<'a, P>(&'a self, pat: P) -> RSplitTerminator<'a, P> where

P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>, `[src]

An iterator over substrings of self, separated by characters matched by a pattern and yielded in reverse order.

The pattern can be a simple &str, char, or a closure that determines the split. Additional libraries might provide more complex patterns like regular expressions.

Equivalent to split, except that the trailing substring is skipped if empty.

This method can be used for string data that is terminated, rather than separated by a pattern.

The returned iterator requires that the pattern supports a reverse search, and it will be double ended if a forward/reverse search yields the same elements.

For iterating from the front, the split_terminator method can be used.

let v: Vec<&str> = "A.B.".rsplit_terminator('.').collect(); assert_eq!(v, ["B", "A"]);

let v: Vec<&str> = "A..B..".rsplit_terminator(".").collect(); assert_eq!(v, ["", "B", "", "A"]);Run

ⓘImportant traits for SplitN<'a, P>

pub fn [splitn](#method.splitn)<'a, P>(&'a self, n: [usize](../primitive.usize.html), pat: P) -> [SplitN](../../std/str/struct.SplitN.html "struct std::str::SplitN")<'a, P> where P: [Pattern](../../std/str/pattern/trait.Pattern.html "trait std::str::pattern::Pattern")<'a>, [src]

An iterator over substrings of the given string slice, separated by a pattern, restricted to returning at most n items.

If n substrings are returned, the last substring (the nth substring) will contain the remainder of the string.

The pattern can be a &str, char, or a closure that determines the split.

The returned iterator will not be double ended, because it is not efficient to support.

If the pattern allows a reverse search, the rsplitn method can be used.

Simple patterns:

let v: Vec<&str> = "Mary had a little lambda".splitn(3, ' ').collect(); assert_eq!(v, ["Mary", "had", "a little lambda"]);

let v: Vec<&str> = "lionXXtigerXleopard".splitn(3, "X").collect(); assert_eq!(v, ["lion", "", "tigerXleopard"]);

let v: Vec<&str> = "abcXdef".splitn(1, 'X').collect(); assert_eq!(v, ["abcXdef"]);

let v: Vec<&str> = "".splitn(1, 'X').collect(); assert_eq!(v, [""]);Run

A more complex pattern, using a closure:

let v: Vec<&str> = "abc1defXghi".splitn(2, |c| c == '1' || c == 'X').collect(); assert_eq!(v, ["abc", "defXghi"]);Run

ⓘImportant traits for RSplitN<'a, P>

pub fn [rsplitn](#method.rsplitn)<'a, P>(&'a self, n: [usize](../primitive.usize.html), pat: P) -> [RSplitN](../../std/str/struct.RSplitN.html "struct std::str::RSplitN")<'a, P> where P: [Pattern](../../std/str/pattern/trait.Pattern.html "trait std::str::pattern::Pattern")<'a>, <P as [Pattern](../../std/str/pattern/trait.Pattern.html "trait std::str::pattern::Pattern")<'a>>::[Searcher](../../std/str/pattern/trait.Pattern.html#associatedtype.Searcher "type std::str::pattern::Pattern::Searcher"): [ReverseSearcher](../../std/str/pattern/trait.ReverseSearcher.html "trait std::str::pattern::ReverseSearcher")<'a>, [src]

An iterator over substrings of this string slice, separated by a pattern, starting from the end of the string, restricted to returning at most n items.

If n substrings are returned, the last substring (the nth substring) will contain the remainder of the string.

The pattern can be a &str, char, or a closure that determines the split.

The returned iterator will not be double ended, because it is not efficient to support.

For splitting from the front, the splitn method can be used.

Simple patterns:

let v: Vec<&str> = "Mary had a little lamb".rsplitn(3, ' ').collect(); assert_eq!(v, ["lamb", "little", "Mary had a"]);

let v: Vec<&str> = "lionXXtigerXleopard".rsplitn(3, 'X').collect(); assert_eq!(v, ["leopard", "tiger", "lionX"]);

let v: Vec<&str> = "lion:🐅:leopard".rsplitn(2, "::").collect(); assert_eq!(v, ["leopard", "lion::tiger"]);Run

A more complex pattern, using a closure:

let v: Vec<&str> = "abc1defXghi".rsplitn(2, |c| c == '1' || c == 'X').collect(); assert_eq!(v, ["ghi", "abc1def"]);Run

ⓘImportant traits for Matches<'a, P>

pub fn [matches](#method.matches)<'a, P>(&'a self, pat: P) -> [Matches](../../std/str/struct.Matches.html "struct std::str::Matches")<'a, P> where P: [Pattern](../../std/str/pattern/trait.Pattern.html "trait std::str::pattern::Pattern")<'a>,

1.2.0

[src]

An iterator over the disjoint matches of a pattern within the given string slice.

The pattern can be a &str, char, or a closure that determines if a character matches.

The returned iterator will be a DoubleEndedIterator if the pattern allows a reverse search and forward/reverse search yields the same elements. This is true for, eg, char but not for &str.

If the pattern allows a reverse search but its results might differ from a forward search, the rmatches method can be used.

Basic usage:

let v: Vec<&str> = "abcXXXabcYYYabc".matches("abc").collect(); assert_eq!(v, ["abc", "abc", "abc"]);

let v: Vec<&str> = "1abc2abc3".matches(char::is_numeric).collect(); assert_eq!(v, ["1", "2", "3"]);Run

`pub fn rmatches<'a, P>(&'a self, pat: P) -> RMatches<'a, P> where

P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>, `

1.2.0

[src]

An iterator over the disjoint matches of a pattern within this string slice, yielded in reverse order.

The pattern can be a &str, char, or a closure that determines if a character matches.

The returned iterator requires that the pattern supports a reverse search, and it will be a DoubleEndedIterator if a forward/reverse search yields the same elements.

For iterating from the front, the matches method can be used.

Basic usage:

let v: Vec<&str> = "abcXXXabcYYYabc".rmatches("abc").collect(); assert_eq!(v, ["abc", "abc", "abc"]);

let v: Vec<&str> = "1abc2abc3".rmatches(char::is_numeric).collect(); assert_eq!(v, ["3", "2", "1"]);Run

`pub fn match_indices<'a, P>(&'a self, pat: P) -> MatchIndices<'a, P> where

P: Pattern<'a>, `

1.5.0

[src]

An iterator over the disjoint matches of a pattern within this string slice as well as the index that the match starts at.

For matches of pat within self that overlap, only the indices corresponding to the first match are returned.

The pattern can be a &str, char, or a closure that determines if a character matches.

The returned iterator will be a DoubleEndedIterator if the pattern allows a reverse search and forward/reverse search yields the same elements. This is true for, eg, char but not for &str.

If the pattern allows a reverse search but its results might differ from a forward search, the rmatch_indices method can be used.

Basic usage:

let v: Vec<_> = "abcXXXabcYYYabc".match_indices("abc").collect(); assert_eq!(v, [(0, "abc"), (6, "abc"), (12, "abc")]);

let v: Vec<_> = "1abcabc2".match_indices("abc").collect(); assert_eq!(v, [(1, "abc"), (4, "abc")]);

let v: Vec<_> = "ababa".match_indices("aba").collect(); assert_eq!(v, [(0, "aba")]); Run

`pub fn rmatch_indices<'a, P>(&'a self, pat: P) -> RMatchIndices<'a, P> where

P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>, `

1.5.0

[src]

An iterator over the disjoint matches of a pattern within self, yielded in reverse order along with the index of the match.

For matches of pat within self that overlap, only the indices corresponding to the last match are returned.

The pattern can be a &str, char, or a closure that determines if a character matches.

The returned iterator requires that the pattern supports a reverse search, and it will be a DoubleEndedIterator if a forward/reverse search yields the same elements.

For iterating from the front, the match_indices method can be used.

Basic usage:

let v: Vec<_> = "abcXXXabcYYYabc".rmatch_indices("abc").collect(); assert_eq!(v, [(12, "abc"), (6, "abc"), (0, "abc")]);

let v: Vec<_> = "1abcabc2".rmatch_indices("abc").collect(); assert_eq!(v, [(4, "abc"), (1, "abc")]);

let v: Vec<_> = "ababa".rmatch_indices("aba").collect(); assert_eq!(v, [(2, "aba")]); Run

pub fn [trim](#method.trim)(&self) -> &[str](../primitive.str.html)[src]

Returns a string slice with leading and trailing whitespace removed.

'Whitespace' is defined according to the terms of the Unicode Derived Core Property White_Space.

Basic usage:

let s = " Hello\tworld\t";

assert_eq!("Hello\tworld", s.trim());Run

pub fn [trim_left](#method.trim%5Fleft)(&self) -> &[str](../primitive.str.html)[src]

Returns a string slice with leading whitespace removed.

'Whitespace' is defined according to the terms of the Unicode Derived Core Property White_Space.

A string is a sequence of bytes. 'Left' in this context means the first position of that byte string; for a language like Arabic or Hebrew which are 'right to left' rather than 'left to right', this will be the right side, not the left.

Basic usage:

let s = " Hello\tworld\t";

assert_eq!("Hello\tworld\t", s.trim_left());Run

Directionality:

let s = " English"; assert!(Some('E') == s.trim_left().chars().next());

let s = " עברית"; assert!(Some('ע') == s.trim_left().chars().next());Run

pub fn [trim_right](#method.trim%5Fright)(&self) -> &[str](../primitive.str.html)[src]

Returns a string slice with trailing whitespace removed.

'Whitespace' is defined according to the terms of the Unicode Derived Core Property White_Space.

A string is a sequence of bytes. 'Right' in this context means the last position of that byte string; for a language like Arabic or Hebrew which are 'right to left' rather than 'left to right', this will be the left side, not the right.

Basic usage:

let s = " Hello\tworld\t";

assert_eq!(" Hello\tworld", s.trim_right());Run

Directionality:

let s = "English "; assert!(Some('h') == s.trim_right().chars().rev().next());

let s = "עברית "; assert!(Some('ת') == s.trim_right().chars().rev().next());Run

`pub fn trim_matches<'a, P>(&'a self, pat: P) -> &'a str where

P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: DoubleEndedSearcher<'a>, `[src]

Returns a string slice with all prefixes and suffixes that match a pattern repeatedly removed.

The pattern can be a char or a closure that determines if a character matches.

Simple patterns:

assert_eq!("11foo1bar11".trim_matches('1'), "foo1bar"); assert_eq!("123foo1bar123".trim_matches(char::is_numeric), "foo1bar");

let x: &[_] = &['1', '2']; assert_eq!("12foo1bar12".trim_matches(x), "foo1bar");Run

A more complex pattern, using a closure:

assert_eq!("1foo1barXX".trim_matches(|c| c == '1' || c == 'X'), "foo1bar");Run

`pub fn trim_left_matches<'a, P>(&'a self, pat: P) -> &'a str where

P: Pattern<'a>, `[src]

Returns a string slice with all prefixes that match a pattern repeatedly removed.

The pattern can be a &str, char, or a closure that determines if a character matches.

A string is a sequence of bytes. 'Left' in this context means the first position of that byte string; for a language like Arabic or Hebrew which are 'right to left' rather than 'left to right', this will be the right side, not the left.

Basic usage:

assert_eq!("11foo1bar11".trim_left_matches('1'), "foo1bar11"); assert_eq!("123foo1bar123".trim_left_matches(char::is_numeric), "foo1bar123");

let x: &[_] = &['1', '2']; assert_eq!("12foo1bar12".trim_left_matches(x), "foo1bar12");Run

`pub fn trim_right_matches<'a, P>(&'a self, pat: P) -> &'a str where

P: Pattern<'a>,
<P as Pattern<'a>>::Searcher: ReverseSearcher<'a>, `[src]

Returns a string slice with all suffixes that match a pattern repeatedly removed.

The pattern can be a &str, char, or a closure that determines if a character matches.

A string is a sequence of bytes. 'Right' in this context means the last position of that byte string; for a language like Arabic or Hebrew which are 'right to left' rather than 'left to right', this will be the left side, not the right.

Simple patterns:

assert_eq!("11foo1bar11".trim_right_matches('1'), "11foo1bar"); assert_eq!("123foo1bar123".trim_right_matches(char::is_numeric), "123foo1bar");

let x: &[_] = &['1', '2']; assert_eq!("12foo1bar12".trim_right_matches(x), "12foo1bar");Run

A more complex pattern, using a closure:

assert_eq!("1fooX".trim_right_matches(|c| c == '1' || c == 'X'), "1foo");Run

`pub fn parse(&self) -> Result<F, <F as FromStr>::Err> where

F: FromStr, `[src]

Parses this string slice into another type.

Because parse is so general, it can cause problems with type inference. As such, parse is one of the few times you'll see the syntax affectionately known as the 'turbofish': ::<>. This helps the inference algorithm understand specifically which type you're trying to parse into.

parse can parse any type that implements the FromStr trait.

Will return Err if it's not possible to parse this string slice into the desired type.

Basic usage

let four: u32 = "4".parse().unwrap();

assert_eq!(4, four);Run

Using the 'turbofish' instead of annotating four:

let four = "4".parse::();

assert_eq!(Ok(4), four);Run

Failing to parse:

let nope = "j".parse::();

assert!(nope.is_err());Run

`pub fn replace<'a, P>(&'a self, from: P, to: &str) -> String where

P: Pattern<'a>, `[src]

Replaces all matches of a pattern with another string.

replace creates a new String, and copies the data from this string slice into it. While doing so, it attempts to find matches of a pattern. If it finds any, it replaces them with the replacement string slice.

Basic usage:

let s = "this is old";

assert_eq!("this is new", s.replace("old", "new"));Run

When the pattern doesn't match:

let s = "this is old"; assert_eq!(s, s.replace("cookie monster", "little lamb"));Run

`pub fn replacen<'a, P>(&'a self, pat: P, to: &str, count: usize) -> String where

P: Pattern<'a>, `

1.16.0

[src]

Replaces first N matches of a pattern with another string.

replacen creates a new String, and copies the data from this string slice into it. While doing so, it attempts to find matches of a pattern. If it finds any, it replaces them with the replacement string slice at most count times.

Basic usage:

let s = "foo foo 123 foo"; assert_eq!("new new 123 foo", s.replacen("foo", "new", 2)); assert_eq!("faa fao 123 foo", s.replacen('o', "a", 3)); assert_eq!("foo foo new23 foo", s.replacen(char::is_numeric, "new", 1));Run

When the pattern doesn't match:

let s = "this is old"; assert_eq!(s, s.replacen("cookie monster", "little lamb", 10));Run

pub fn [to_lowercase](#method.to%5Flowercase)(&self) -> [String](../../std/string/struct.String.html "struct std:🧵:String")

1.2.0

[src]

Returns the lowercase equivalent of this string slice, as a new String.

'Lowercase' is defined according to the terms of the Unicode Derived Core PropertyLowercase.

Since some characters can expand into multiple characters when changing the case, this function returns a String instead of modifying the parameter in-place.

Basic usage:

let s = "HELLO";

assert_eq!("hello", s.to_lowercase());Run

A tricky example, with sigma:

let sigma = "Σ";

assert_eq!("σ", sigma.to_lowercase());

let odysseus = "ὈΔΥΣΣΕΎΣ";

assert_eq!("ὀδυσσεύς", odysseus.to_lowercase());Run

Languages without case are not changed:

let new_year = "农历新年";

assert_eq!(new_year, new_year.to_lowercase());Run

pub fn [to_uppercase](#method.to%5Fuppercase)(&self) -> [String](../../std/string/struct.String.html "struct std:🧵:String")

1.2.0

[src]

Returns the uppercase equivalent of this string slice, as a new String.

'Uppercase' is defined according to the terms of the Unicode Derived Core PropertyUppercase.

Since some characters can expand into multiple characters when changing the case, this function returns a String instead of modifying the parameter in-place.

Basic usage:

let s = "hello";

assert_eq!("HELLO", s.to_uppercase());Run

Scripts without case are not changed:

let new_year = "农历新年";

assert_eq!(new_year, new_year.to_uppercase());Run

pub fn [escape_debug](#method.escape%5Fdebug)(&self) -> [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

🔬 This is a nightly-only experimental API. (str_escape #27791)

return type may change to be an iterator

pub fn [escape_default](#method.escape%5Fdefault)(&self) -> [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

🔬 This is a nightly-only experimental API. (str_escape #27791)

return type may change to be an iterator

pub fn [escape_unicode](#method.escape%5Funicode)(&self) -> [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

🔬 This is a nightly-only experimental API. (str_escape #27791)

return type may change to be an iterator

pub fn [repeat](#method.repeat)(&self, n: [usize](../primitive.usize.html)) -> [String](../../std/string/struct.String.html "struct std:🧵:String")

1.16.0

[src]

Create a String by repeating a string n times.

Basic usage:

assert_eq!("abc".repeat(4), String::from("abcabcabcabc"));Run

pub fn [is_ascii](#method.is%5Fascii)(&self) -> [bool](../primitive.bool.html)

1.23.0

[src]

Checks if all characters in this string are within the ASCII range.

let ascii = "hello!\n"; let non_ascii = "Grüße, Jürgen ❤";

assert!(ascii.is_ascii()); assert!(!non_ascii.is_ascii());Run

pub fn [to_ascii_uppercase](#method.to%5Fascii%5Fuppercase)(&self) -> [String](../../std/string/struct.String.html "struct std:🧵:String")

1.23.0

[src]

Returns a copy of this string where each character is mapped to its ASCII upper case equivalent.

ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', but non-ASCII letters are unchanged.

To uppercase the value in-place, use make_ascii_uppercase.

To uppercase ASCII characters in addition to non-ASCII characters, useto_uppercase.

let s = "Grüße, Jürgen ❤";

assert_eq!("GRüßE, JüRGEN ❤", s.to_ascii_uppercase());Run

pub fn [to_ascii_lowercase](#method.to%5Fascii%5Flowercase)(&self) -> [String](../../std/string/struct.String.html "struct std:🧵:String")

1.23.0

[src]

Returns a copy of this string where each character is mapped to its ASCII lower case equivalent.

ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', but non-ASCII letters are unchanged.

To lowercase the value in-place, use make_ascii_lowercase.

To lowercase ASCII characters in addition to non-ASCII characters, useto_lowercase.

let s = "Grüße, Jürgen ❤";

assert_eq!("grüße, jürgen ❤", s.to_ascii_lowercase());Run

pub fn [eq_ignore_ascii_case](#method.eq%5Fignore%5Fascii%5Fcase)(&self, other: &[str](../primitive.str.html)) -> [bool](../primitive.bool.html)

1.23.0

[src]

Checks that two strings are an ASCII case-insensitive match.

Same as to_ascii_lowercase(a) == to_ascii_lowercase(b), but without allocating and copying temporaries.

assert!("Ferris".eq_ignore_ascii_case("FERRIS")); assert!("Ferrös".eq_ignore_ascii_case("FERRöS")); assert!(!"Ferrös".eq_ignore_ascii_case("FERRÖS"));Run

pub fn [make_ascii_uppercase](#method.make%5Fascii%5Fuppercase)(&mut self)

1.23.0

[src]

Converts this string to its ASCII upper case equivalent in-place.

ASCII letters 'a' to 'z' are mapped to 'A' to 'Z', but non-ASCII letters are unchanged.

To return a new uppercased value without modifying the existing one, useto_ascii_uppercase.

pub fn [make_ascii_lowercase](#method.make%5Fascii%5Flowercase)(&mut self)

1.23.0

[src]

Converts this string to its ASCII lower case equivalent in-place.

ASCII letters 'A' to 'Z' are mapped to 'a' to 'z', but non-ASCII letters are unchanged.

To return a new lowercased value without modifying the existing one, useto_ascii_lowercase.

impl<'a, 'b> [Pattern](../../std/str/pattern/trait.Pattern.html "trait std::str::pattern::Pattern")<'a> for &'b [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

A convenience impl that delegates to the impl for &str

type [Searcher](../../std/str/pattern/trait.Pattern.html#associatedtype.Searcher) = <&'b [str](../primitive.str.html) as [Pattern](../../std/str/pattern/trait.Pattern.html "trait std::str::pattern::Pattern")<'a>>::[Searcher](../../std/str/pattern/trait.Pattern.html#associatedtype.Searcher "type std::str::pattern::Pattern::Searcher")

🔬 This is a nightly-only experimental API. (pattern #27721)

API not fully fleshed out and ready to be stabilized

Associated searcher for this pattern

fn [into_searcher](../../std/str/pattern/trait.Pattern.html#tymethod.into%5Fsearcher)(self, haystack: &'a [str](../primitive.str.html)) -> <&'b [str](../primitive.str.html) as [Pattern](../../std/str/pattern/trait.Pattern.html "trait std::str::pattern::Pattern")<'a>>::[Searcher](../../std/str/pattern/trait.Pattern.html#associatedtype.Searcher "type std::str::pattern::Pattern::Searcher")[src]

🔬 This is a nightly-only experimental API. (pattern #27721)

API not fully fleshed out and ready to be stabilized

Constructs the associated searcher from self and the haystack to search in. Read more

fn [is_contained_in](../../std/str/pattern/trait.Pattern.html#method.is%5Fcontained%5Fin)(self, haystack: &'a [str](../primitive.str.html)) -> [bool](../primitive.bool.html)[src]

🔬 This is a nightly-only experimental API. (pattern #27721)

API not fully fleshed out and ready to be stabilized

Checks whether the pattern matches anywhere in the haystack

fn [is_prefix_of](../../std/str/pattern/trait.Pattern.html#method.is%5Fprefix%5Fof)(self, haystack: &'a [str](../primitive.str.html)) -> [bool](../primitive.bool.html)[src]

🔬 This is a nightly-only experimental API. (pattern #27721)

API not fully fleshed out and ready to be stabilized

Checks whether the pattern matches at the front of the haystack

`fn is_suffix_of(self, haystack: &'a str) -> bool where

Self::Searcher: ReverseSearcher<'a>, `[src]

🔬 This is a nightly-only experimental API. (pattern #27721)

API not fully fleshed out and ready to be stabilized

Checks whether the pattern matches at the back of the haystack

impl [From](../../std/convert/trait.From.html "trait std::convert::From")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [Rc](../../std/rc/struct.Rc.html "struct std::rc::Rc")<[str](../primitive.str.html)>

1.21.0

[src]

impl [From](../../std/convert/trait.From.html "trait std::convert::From")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [Box](../../std/boxed/struct.Box.html "struct std::boxed::Box")<[str](../primitive.str.html)>

1.20.0

[src]

impl [From](../../std/convert/trait.From.html "trait std::convert::From")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [Arc](../../std/sync/struct.Arc.html "struct std::sync::Arc")<[str](../primitive.str.html)>

1.21.0

[src]

impl [From](../../std/convert/trait.From.html "trait std::convert::From")<[Box](../../std/boxed/struct.Box.html "struct std::boxed::Box")<[str](../primitive.str.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.18.0

[src]

impl<'a> [From](../../std/convert/trait.From.html "trait std::convert::From")<&'a [str](../primitive.str.html)> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [From](../../std/convert/trait.From.html "trait std::convert::From")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [Vec](../../std/vec/struct.Vec.html "struct std::vec::Vec")<[u8](../primitive.u8.html)>

1.14.0

[src]

impl<'a> [From](../../std/convert/trait.From.html "trait std::convert::From")<[Cow](../../std/borrow/enum.Cow.html "enum std::borrow::Cow")<'a, [str](../primitive.str.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.14.0

[src]

impl<'a> [From](../../std/convert/trait.From.html "trait std::convert::From")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [Cow](../../std/borrow/enum.Cow.html "enum std::borrow::Cow")<'a, [str](../primitive.str.html)>[src]

impl [IndexMut](../../std/ops/trait.IndexMut.html "trait std::ops::IndexMut")<[RangeTo](../../std/ops/struct.RangeTo.html "struct std::ops::RangeTo")<[usize](../primitive.usize.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.3.0

[src]

impl [IndexMut](../../std/ops/trait.IndexMut.html "trait std::ops::IndexMut")<[RangeInclusive](../../std/ops/struct.RangeInclusive.html "struct std::ops::RangeInclusive")<[usize](../primitive.usize.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [IndexMut](../../std/ops/trait.IndexMut.html "trait std::ops::IndexMut")<[RangeToInclusive](../../std/ops/struct.RangeToInclusive.html "struct std::ops::RangeToInclusive")<[usize](../primitive.usize.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [IndexMut](../../std/ops/trait.IndexMut.html "trait std::ops::IndexMut")<[Range](../../std/ops/struct.Range.html "struct std::ops::Range")<[usize](../primitive.usize.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.3.0

[src]

impl [IndexMut](../../std/ops/trait.IndexMut.html "trait std::ops::IndexMut")<[RangeFrom](../../std/ops/struct.RangeFrom.html "struct std::ops::RangeFrom")<[usize](../primitive.usize.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.3.0

[src]

impl [IndexMut](../../std/ops/trait.IndexMut.html "trait std::ops::IndexMut")<[RangeFull](../../std/ops/struct.RangeFull.html "struct std::ops::RangeFull")> for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.3.0

[src]

impl [FromStr](../../std/str/trait.FromStr.html "trait std::str::FromStr") for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [ToString](../../std/string/trait.ToString.html "trait std:🧵:ToString") for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.17.0

[src]

impl [Borrow](../../std/borrow/trait.Borrow.html "trait std::borrow::Borrow")<[str](../primitive.str.html)> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [Ord](../../std/cmp/trait.Ord.html "trait std::cmp::Ord") for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [Clone](../../std/clone/trait.Clone.html "trait std::clone::Clone") for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [DerefMut](../../std/ops/trait.DerefMut.html "trait std::ops::DerefMut") for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.3.0

[src]

impl [Extend](../../std/iter/trait.Extend.html "trait std::iter::Extend")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.4.0

[src]

impl [Extend](../../std/iter/trait.Extend.html "trait std::iter::Extend")<[char](../primitive.char.html)> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl<'a> [Extend](../../std/iter/trait.Extend.html "trait std::iter::Extend")<[Cow](../../std/borrow/enum.Cow.html "enum std::borrow::Cow")<'a, [str](../primitive.str.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.19.0

[src]

impl<'a> [Extend](../../std/iter/trait.Extend.html "trait std::iter::Extend")<&'a [char](../primitive.char.html)> for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.2.0

[src]

impl<'a> [Extend](../../std/iter/trait.Extend.html "trait std::iter::Extend")<&'a [str](../primitive.str.html)> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [Hash](../../std/hash/trait.Hash.html "trait std::hash::Hash") for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [Index](../../std/ops/trait.Index.html "trait std::ops::Index")<[RangeInclusive](../../std/ops/struct.RangeInclusive.html "struct std::ops::RangeInclusive")<[usize](../primitive.usize.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [Index](../../std/ops/trait.Index.html "trait std::ops::Index")<[Range](../../std/ops/struct.Range.html "struct std::ops::Range")<[usize](../primitive.usize.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [Index](../../std/ops/trait.Index.html "trait std::ops::Index")<[RangeTo](../../std/ops/struct.RangeTo.html "struct std::ops::RangeTo")<[usize](../primitive.usize.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [Index](../../std/ops/trait.Index.html "trait std::ops::Index")<[RangeFull](../../std/ops/struct.RangeFull.html "struct std::ops::RangeFull")> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [Index](../../std/ops/trait.Index.html "trait std::ops::Index")<[RangeFrom](../../std/ops/struct.RangeFrom.html "struct std::ops::RangeFrom")<[usize](../primitive.usize.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [Index](../../std/ops/trait.Index.html "trait std::ops::Index")<[RangeToInclusive](../../std/ops/struct.RangeToInclusive.html "struct std::ops::RangeToInclusive")<[usize](../primitive.usize.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl<'a> [Add](../../std/ops/trait.Add.html "trait std::ops::Add")<&'a [str](../primitive.str.html)> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

Implements the + operator for concatenating two strings.

This consumes the String on the left-hand side and re-uses its buffer (growing it if necessary). This is done to avoid allocating a new String and copying the entire contents on every operation, which would lead to O(n^2) running time when building an n-byte string by repeated concatenation.

The string on the right-hand side is only borrowed; its contents are copied into the returnedString.

Concatenating two Strings takes the first by value and borrows the second:

let a = String::from("hello"); let b = String::from(" world"); let c = a + &b; Run

If you want to keep using the first String, you can clone it and append to the clone instead:

let a = String::from("hello"); let b = String::from(" world"); let c = a.clone() + &b; Run

Concatenating &str slices can be done by converting the first to a String:

let a = "hello"; let b = " world"; let c = a.to_string() + b;Run

impl<'a, 'b> [PartialEq](../../std/cmp/trait.PartialEq.html "trait std::cmp::PartialEq")<[str](../primitive.str.html)> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

fn [eq](../../std/cmp/trait.PartialEq.html#tymethod.eq)(&self, other: &[str](../primitive.str.html)) -> [bool](../primitive.bool.html)[src]

This method tests for self and other values to be equal, and is used by ==. Read more

fn [ne](../../std/cmp/trait.PartialEq.html#method.ne)(&self, other: &[str](../primitive.str.html)) -> [bool](../primitive.bool.html)[src]

This method tests for !=.

impl<'a, 'b> [PartialEq](../../std/cmp/trait.PartialEq.html "trait std::cmp::PartialEq")<&'a [str](../primitive.str.html)> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

fn [eq](../../std/cmp/trait.PartialEq.html#tymethod.eq)(&self, other: &&'a [str](../primitive.str.html)) -> [bool](../primitive.bool.html)[src]

This method tests for self and other values to be equal, and is used by ==. Read more

fn [ne](../../std/cmp/trait.PartialEq.html#method.ne)(&self, other: &&'a [str](../primitive.str.html)) -> [bool](../primitive.bool.html)[src]

This method tests for !=.

impl<'a, 'b> [PartialEq](../../std/cmp/trait.PartialEq.html "trait std::cmp::PartialEq")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [Cow](../../std/borrow/enum.Cow.html "enum std::borrow::Cow")<'a, [str](../primitive.str.html)>[src]

impl<'a, 'b> [PartialEq](../../std/cmp/trait.PartialEq.html "trait std::cmp::PartialEq")<[Cow](../../std/borrow/enum.Cow.html "enum std::borrow::Cow")<'a, [str](../primitive.str.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl<'a, 'b> [PartialEq](../../std/cmp/trait.PartialEq.html "trait std::cmp::PartialEq")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for &'a [str](../primitive.str.html)[src]

impl<'a, 'b> [PartialEq](../../std/cmp/trait.PartialEq.html "trait std::cmp::PartialEq")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [str](../primitive.str.html)[src]

impl [PartialEq](../../std/cmp/trait.PartialEq.html "trait std::cmp::PartialEq")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [Display](../../std/fmt/trait.Display.html "trait std::fmt::Display") for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [Eq](../../std/cmp/trait.Eq.html "trait std::cmp::Eq") for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl<'a> [AddAssign](../../std/ops/trait.AddAssign.html "trait std::ops::AddAssign")<&'a [str](../primitive.str.html)> for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.12.0

[src]

Implements the += operator for appending to a String.

This has the same behavior as the push_str method.

impl [AsRef](../../std/convert/trait.AsRef.html "trait std::convert::AsRef")<[str](../primitive.str.html)> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [AsRef](../../std/convert/trait.AsRef.html "trait std::convert::AsRef")<[[](../primitive.slice.html)[u8](../primitive.u8.html)[]](../primitive.slice.html)> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [Default](../../std/default/trait.Default.html "trait std::default::Default") for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [FromIterator](../../std/iter/trait.FromIterator.html "trait std::iter::FromIterator")<[char](../primitive.char.html)> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl<'a> [FromIterator](../../std/iter/trait.FromIterator.html "trait std::iter::FromIterator")<&'a [char](../primitive.char.html)> for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.17.0

[src]

impl [FromIterator](../../std/iter/trait.FromIterator.html "trait std::iter::FromIterator")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.4.0

[src]

impl<'a> [FromIterator](../../std/iter/trait.FromIterator.html "trait std::iter::FromIterator")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [Cow](../../std/borrow/enum.Cow.html "enum std::borrow::Cow")<'a, [str](../primitive.str.html)>

1.12.0

[src]

impl<'a> [FromIterator](../../std/iter/trait.FromIterator.html "trait std::iter::FromIterator")<&'a [str](../primitive.str.html)> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl<'a> [FromIterator](../../std/iter/trait.FromIterator.html "trait std::iter::FromIterator")<[Cow](../../std/borrow/enum.Cow.html "enum std::borrow::Cow")<'a, [str](../primitive.str.html)>> for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.19.0

[src]

impl [Debug](../../std/fmt/trait.Debug.html "trait std::fmt::Debug") for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [Deref](../../std/ops/trait.Deref.html "trait std::ops::Deref") for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [PartialOrd](../../std/cmp/trait.PartialOrd.html "trait std::cmp::PartialOrd")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [Write](../../std/fmt/trait.Write.html "trait std::fmt::Write") for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [From](../../std/convert/trait.From.html "trait std::convert::From")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [Box](../../std/boxed/struct.Box.html "struct std::boxed::Box")<[Error](../../std/error/trait.Error.html "trait std::error::Error") + [Send](../../std/marker/trait.Send.html "trait std:📑:Send") + [Sync](../../std/marker/trait.Sync.html "trait std:📑:Sync")>[src]

impl [From](../../std/convert/trait.From.html "trait std::convert::From")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [Box](../../std/boxed/struct.Box.html "struct std::boxed::Box")<[Error](../../std/error/trait.Error.html "trait std::error::Error")>

1.6.0

[src]

impl [From](../../std/convert/trait.From.html "trait std::convert::From")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [OsString](../../std/ffi/struct.OsString.html "struct std::ffi::OsString")[src]

impl [AsRef](../../std/convert/trait.AsRef.html "trait std::convert::AsRef")<[OsStr](../../std/ffi/struct.OsStr.html "struct std::ffi::OsStr")> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]

impl [ToSocketAddrs](../../std/net/trait.ToSocketAddrs.html "trait std:🥅:ToSocketAddrs") for [String](../../std/string/struct.String.html "struct std:🧵:String")

1.16.0

[src]

impl [From](../../std/convert/trait.From.html "trait std::convert::From")<[String](../../std/string/struct.String.html "struct std:🧵:String")> for [PathBuf](../../std/path/struct.PathBuf.html "struct std::path::PathBuf")[src]

impl [AsRef](../../std/convert/trait.AsRef.html "trait std::convert::AsRef")<[Path](../../std/path/struct.Path.html "struct std::path::Path")> for [String](../../std/string/struct.String.html "struct std:🧵:String")[src]