std.algorithm.mutation - D Programming Language (original) (raw)

size_t bringToFront(InputRange, ForwardRange)(InputRange front, ForwardRange back)
if (isInputRange!InputRange && isForwardRange!ForwardRange);

bringToFront takes two ranges front and back, which may be of different types. Considering the concatenation of front andback one unified range, bringToFront rotates that unified range such that all elements in back are brought to the beginning of the unified range. The relative ordering of elements in frontand back, respectively, remains unchanged.

The bringToFront function treats strings at the code unit level and it is not concerned with Unicode character integrity.bringToFront is designed as a function for moving elements in ranges, not as a string function.

Performs Ο(max(front.length, back.length)) evaluations of swap.

The bringToFront function can rotate elements in one buffer left or right, swap buffers of equal length, and even move elements across disjoint buffers of different types and different lengths.

PreconditionsEither front and back are disjoint, or back is reachable from front and front is not reachable from back.

Returns:

The number of elements brought to the front, i.e., the length of back.

Examples:

The simplest use of bringToFront is for rotating elements in a buffer. For example:

auto arr = [4, 5, 6, 7, 1, 2, 3]; auto p = bringToFront(arr[0 .. 4], arr[4 .. $]); writeln(p); writeln(arr);

Examples:

The front range may actually "step over" the backrange. This is very useful with forward ranges that cannot compute comfortably right-bounded subranges like arr[0 .. 4] above. In the example below, r2 is a right subrange of r1.

import std.algorithm.comparison : equal; import std.container : SList; import std.range.primitives : popFrontN;

auto list = SList!(int)(4, 5, 6, 7, 1, 2, 3); auto r1 = list[]; auto r2 = list[]; popFrontN(r2, 4); assert(equal(r2, [ 1, 2, 3 ])); bringToFront(r1, r2); assert(equal(list[], [ 1, 2, 3, 4, 5, 6, 7 ]));

Examples:

Elements can be swapped across ranges of different types:

import std.algorithm.comparison : equal; import std.container : SList;

auto list = SList!(int)(4, 5, 6, 7); auto vec = [ 1, 2, 3 ]; bringToFront(list[], vec); assert(equal(list[], [ 1, 2, 3, 4 ])); assert(equal(vec, [ 5, 6, 7 ]));

Examples:

Unicode integrity is not preserved:

import std.string : representation; auto ar = representation("a".dup); auto br = representation("ç".dup);

bringToFront(ar, br);

auto a = cast(char[]) ar; auto b = cast(char[]) br;

writeln(a); writeln(b);

TargetRange copy(SourceRange, TargetRange)(SourceRange source, TargetRange target)
if (isInputRange!SourceRange && isOutputRange!(TargetRange, ElementType!SourceRange));

Copies the content of source into target and returns the remaining (unfilled) part of target.

Preconditions target shall have enough room to accommodate the entirety of source.

Parameters:

Returns:

The unfilled part of target

Examples:

int[] a = [ 1, 5 ]; int[] b = [ 9, 8 ]; int[] buf = new int[](a.length + b.length + 10); auto rem = a.copy(buf); rem = b.copy(rem); writeln(buf[0 .. a.length + b.length]); assert(rem.length == 10);

Examples:

As long as the target range elements support assignment from source range elements, different types of ranges are accepted:

float[] src = [ 1.0f, 5 ]; double[] dest = new double[src.length]; src.copy(dest);

Examples:

To copy at most n elements from a range, you may want to usestd.range.take:

import std.range; int[] src = [ 1, 5, 8, 9, 10 ]; auto dest = new int; src.take(dest.length).copy(dest); writeln(dest);

Examples:

To copy just those elements from a range that satisfy a predicate, use filter:

import std.algorithm.iteration : filter; int[] src = [ 1, 5, 8, 9, 10, 1, 2, 0 ]; auto dest = new int[src.length]; auto rem = src .filter!(a => (a & 1) == 1) .copy(dest); writeln(dest[0 .. $ - rem.length]);

Examples:

std.range.retro can be used to achieve behavior similar toSTL's copy_backward':

import std.algorithm, std.range; int[] src = [1, 2, 4]; int[] dest = [0, 0, 0, 0, 0]; src.retro.copy(dest.retro); writeln(dest);

void fill(Range, Value)(auto ref Range range, auto ref Value value)
if (isInputRange!Range && is(typeof(range.front = value)) || isSomeChar!Value && is(typeof(range[] = value)));

void fill(InputRange, ForwardRange)(InputRange range, ForwardRange filler)
if (isInputRange!InputRange && (isForwardRange!ForwardRange || isInputRange!ForwardRange && isInfinite!ForwardRange) && is(typeof(InputRange.init.front = ForwardRange.init.front)));

Assigns value to each element of input range range.

Alternatively, instead of using a single value to fill the range, a filler forward rangecan be provided. The length of filler and range do not need to match, butfiller must not be empty.

Parameters:

Throws:

If filler is empty.

Examples:

int[] a = [ 1, 2, 3, 4 ]; fill(a, 5); writeln(a);

Examples:

int[] a = [ 1, 2, 3, 4, 5 ]; int[] b = [ 8, 9 ]; fill(a, b); writeln(a);

void initializeAll(Range)(Range range)
if (isInputRange!Range && hasLvalueElements!Range && hasAssignableElements!Range && __traits(compiles, () { static ElementType!Range _; } ));

void initializeAll(Range)(Range range)
if (is(Range == char[]) || is(Range == wchar[]));

Initializes all elements of range with their .init value. Assumes that the elements of the range are uninitialized.

This function is unavailable if T is a struct and T.this() is annotated with @disable.

Parameters:

Examples:

import core.stdc.stdlib : malloc, free;

struct S { int a = 10; }

auto s = (cast(S*) malloc(5 * S.sizeof))[0 .. 5]; initializeAll(s); writeln(s); scope(exit) free(s.ptr);

void move(T)(ref T source, ref T target)
if (__traits(compiles, target = T.init));

void move(T)(ref T source, ref T target)
if (!__traits(compiles, imported!"std.traits".lvalueOf!T = T.init));

T move(T)(ref return scope T source);

Moves source into target, via a destructive copy when necessary.

If T is a struct with a destructor or postblit defined, source is reset to its .init value after it is moved into target, otherwise it is left unchanged.

PreconditionsIf source has internal pointers that point to itself and doesn't define opPostMove, it cannot be moved, and will trigger an assertion failure.

Parameters:

Examples:

For non-struct types, move just performs target = source:

Object obj1 = new Object; Object obj2 = obj1; Object obj3;

move(obj2, obj3); assert(obj3 is obj1); assert(obj2 is obj1);

Examples:

struct S1 { int a = 1; int b = 2; } S1 s11 = { 10, 11 }; S1 s12;

move(s11, s12);

writeln(s12); writeln(s11); struct S2 { int a = 1; int b = 2;

~this() pure nothrow @safe @nogc { }

} S2 s21 = { 3, 4 }; S2 s22;

move(s21, s22);

writeln(s21); writeln(s22);

Examples:

Non-copyable structs can still be moved:

struct S { int a = 1; @disable this(this); ~this() pure nothrow @safe @nogc {} } S s1; s1.a = 2; S s2 = move(s1); writeln(s1.a); writeln(s2.a);

Examples:

opPostMove will be called if defined:

struct S { int a; void opPostMove(const ref S old) { writeln(a); a++; } } S s1; s1.a = 41; S s2 = move(s1); writeln(s2.a);

pure @system void moveEmplace(T)(ref T source, ref T target);

Similar to move but assumes target is uninitialized. This is more efficient because source can be blitted over target without destroying or initializing it first.

Parameters:

Examples:

static struct Foo { pure nothrow @nogc: this(int* ptr) { _ptr = ptr; } ~this() { if (_ptr) ++_ptr; } int _ptr; }

int val; Foo foo1 = void; auto foo2 = Foo(&val); assert(foo2._ptr is &val);

moveEmplace(foo2, foo1); assert(foo1._ptr is &val); assert(foo2._ptr is null); writeln(val);

InputRange2 moveAll(InputRange1, InputRange2)(InputRange1 src, InputRange2 tgt)
if (isInputRange!InputRange1 && isInputRange!InputRange2 && is(typeof(move(src.front, tgt.front))));

Calls move(a, b) for each element a in src and the corresponding element b in tgt, in increasing order.

Preconditions walkLength(src) <= walkLength(tgt). This precondition will be asserted. If you cannot ensure there is enough room intgt to accommodate all of src use moveSome instead.

Parameters:

Returns:

The leftover portion of tgt after all elements from src have been moved.

Examples:

int[3] a = [ 1, 2, 3 ]; int[5] b; assert(moveAll(a[], b[]) is b[3 .. $]); writeln(a[]); int[3] cmp = [ 1, 2, 3 ]; writeln(a[]);

@system InputRange2 moveEmplaceAll(InputRange1, InputRange2)(InputRange1 src, InputRange2 tgt)
if (isInputRange!InputRange1 && isInputRange!InputRange2 && is(typeof(moveEmplace(src.front, tgt.front))));

Similar to moveAll but assumes all elements in tgt are uninitialized. Uses moveEmplace to move elements fromsrc over elements from tgt.

Examples:

static struct Foo { ~this() pure nothrow @nogc { if (_ptr) ++_ptr; } int _ptr; } int[3] refs = [0, 1, 2]; Foo[3] src = [Foo(&refs[0]), Foo(&refs[1]), Foo(&refs[2])]; Foo[5] dst = void;

auto tail = moveEmplaceAll(src[], dst[]); assert(tail.length == 2); initializeAll(tail);

import std.algorithm.searching : all; assert(src[].all!(e => e._ptr is null)); assert(dst[0 .. 3].all!(e => e._ptr !is null));

Tuple!(InputRange1, InputRange2) moveSome(InputRange1, InputRange2)(InputRange1 src, InputRange2 tgt)
if (isInputRange!InputRange1 && isInputRange!InputRange2 && is(typeof(move(src.front, tgt.front))));

Calls move(a, b) for each element a in src and the corresponding element b in tgt, in increasing order, stopping when either range has been exhausted.

Parameters:

Returns:

The leftover portions of the two ranges after one or the other of the ranges have been exhausted.

Examples:

int[5] a = [ 1, 2, 3, 4, 5 ]; int[3] b; assert(moveSome(a[], b[])[0] is a[3 .. $]); writeln(a[0 .. 3]); writeln(a);

@system Tuple!(InputRange1, InputRange2) moveEmplaceSome(InputRange1, InputRange2)(InputRange1 src, InputRange2 tgt)
if (isInputRange!InputRange1 && isInputRange!InputRange2 && is(typeof(move(src.front, tgt.front))));

Same as moveSome but assumes all elements in tgt are uninitialized. Uses moveEmplace to move elements fromsrc over elements from tgt.

Examples:

static struct Foo { ~this() pure nothrow @nogc { if (_ptr) ++_ptr; } int _ptr; } int[4] refs = [0, 1, 2, 3]; Foo[4] src = [Foo(&refs[0]), Foo(&refs[1]), Foo(&refs[2]), Foo(&refs[3])]; Foo[3] dst = void;

auto res = moveEmplaceSome(src[], dst[]); writeln(res.length); import std.algorithm.searching : all; assert(src[0 .. 3].all!(e => e._ptr is null)); assert(src[3]._ptr !is null); assert(dst[].all!(e => e._ptr !is null));

Defines the swapping strategy for algorithms that need to swap elements in a range (such as partition and sort). The strategy concerns the swapping of elements that are not the core concern of the algorithm. For example, consider an algorithm that sorts [ "abc", "b", "aBc" ] according to toUpper(a) < toUpper(b). That algorithm might choose to swap the two equivalent strings "abc"and "aBc". That does not affect the sorting since both["abc", "aBc", "b" ] and [ "aBc", "abc", "b" ] are valid outcomes.

Some situations require that the algorithm must NOT ever change the relative ordering of equivalent elements (in the example above, only[ "abc", "aBc", "b" ] would be the correct result). Such algorithms are called stable. If the ordering algorithm may swap equivalent elements discretionarily, the ordering is called unstable.

Yet another class of algorithms may choose an intermediate tradeoff by being stable only on a well-defined subrange of the range. There is no established terminology for such behavior; this library calls it semistable.

Generally, the stable ordering strategy may be more costly in time and/or space than the other two because it imposes additional constraints. Similarly, semistable may be costlier than unstable. As (semi-)stability is not needed very often, the ordering algorithms in this module parameterized by SwapStrategy all choose SwapStrategy.unstable as the default.

Examples:

int[] a = [0, 1, 2, 3]; writeln(remove!(SwapStrategy.stable)(a, 1)); a = [0, 1, 2, 3]; writeln(remove!(SwapStrategy.unstable)(a, 1));

Examples:

import std.algorithm.sorting : partition;

auto arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; writeln(partition!(a => a > 3, SwapStrategy.stable)(arr)); writeln(arr); arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; writeln(partition!(a => a > 3, SwapStrategy.semistable)(arr)); writeln(arr); arr = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]; writeln(partition!(a => a > 3, SwapStrategy.unstable)(arr)); writeln(arr);

Allows freely swapping of elements as long as the output satisfies the algorithm's requirements.

In algorithms partitioning ranges in two, preserve relative ordering of elements only to the left of the partition point.

Preserve the relative ordering of elements to the largest extent allowed by the algorithm's requirements.

Range remove(SwapStrategy s = SwapStrategy.stable, Range, Offset...)(Range range, Offset offset)
if (Offset.length >= 1 && allSatisfy!(isValidIntegralTuple, Offset));

Range remove(SwapStrategy s = SwapStrategy.stable, Range, Offset...)(Range range, Offset offset)
if (Offset.length >= 1 && !allSatisfy!(isValidIntegralTuple, Offset));

Eliminates elements at given offsets from range and returns the shortened range.

For example, here is how to remove a single element from an array:

import std.algorithm.mutation; string[] a = [ "a", "b", "c", "d" ]; a = a.remove(1); assert(a == [ "a", "c", "d"]);

Note that remove does not change the length of the original range directly; instead, it returns the shortened range. If its return value is not assigned to the original range, the original range will retain its original length, though its contents will have changed:

import std.algorithm.mutation; int[] a = [ 3, 5, 7, 8 ]; assert(remove(a, 1) == [ 3, 7, 8 ]); assert(a == [ 3, 7, 8, 8 ]);

The element at offset 1 has been removed and the rest of the elements have shifted up to fill its place, however, the original array remains of the same length. This is because all functions in std.algorithm only change content, not topology. The value 8 is repeated because move was invoked to rearrange elements, and on integers move simply copies the source to the destination. To replace a with the effect of the removal, simply assign the slice returned by remove to it, as shown in the first example.

Removing multiple elements

Multiple indices can be passed into remove. In that case, elements at the respective indices are all removed. The indices must be passed in increasing order, otherwise an exception occurs.

import std.algorithm.mutation; int[] a = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ]; assert(remove(a, 1, 3, 5) == [ 0, 2, 4, 6, 7, 8, 9, 10 ]);

Note that all indices refer to slots in the original array, not in the array as it is being progressively shortened.

Tuples of two integral offsets can be supplied to remove a range of indices:

import std.algorithm.mutation, std.typecons; int[] a = [ 3, 4, 5, 6, 7]; assert(remove(a, tuple(1, 3)) == [ 3, 6, 7 ]);

The tuple passes in a range closed to the left and open to the right (consistent with built-in slices), e.g. tuple(1, 3)means indices 1 and 2 but not 3.

Finally, any combination of integral offsets and tuples composed of two integral offsets can be passed in:

import std.algorithm.mutation, std.typecons; int[] a = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ]; a = remove(a, 1, tuple(3, 5), 9); assert(a == [ 0, 2, 5, 6, 7, 8, 10 ]);

In this case, the slots at positions 1, 3, 4, and 9 are removed from the array.

Moving strategy

If the need is to remove some elements in the range but the order of the remaining elements does not have to be preserved, you may want to pass SwapStrategy.unstable to remove.

import std.algorithm.mutation; int[] a = [ 0, 1, 2, 3 ]; assert(remove!(SwapStrategy.unstable)(a, 1) == [ 0, 3, 2 ]);

In the case above, the element at slot 1 is removed, but replaced with the last element of the range. Taking advantage of the relaxation of the stability requirement, remove moved elements from the end of the array over the slots to be removed. This way there is less data movement to be done which improves the execution time of the function.

remove works on bidirectional ranges that have assignable lvalue elements. The moving strategy is (listed from fastest to slowest):

• If s == SwapStrategy.unstable && isRandomAccessRange!Range && hasLength!Range && hasLvalueElements!Range, then elements are moved from the end of the range into the slots to be filled. In this case, the absolute minimum of moves is performed.
• Otherwise, if s == SwapStrategy.unstable && isBidirectionalRange!Range && hasLength!Range && hasLvalueElements!Range, then elements are still moved from the end of the range, but time is spent on advancing between slots by repeated calls to range.popFront.
• Otherwise, elements are moved incrementally towards the front of range; a given element is never moved several times, but more elements are moved than in the previous cases.

Parameters:

Returns:

A range containing elements of range with 1 or more elements removed.

Examples:

import std.typecons : tuple;

auto a = [ 0, 1, 2, 3, 4, 5 ]; writeln(remove!(SwapStrategy.stable)(a, 1)); a = [ 0, 1, 2, 3, 4, 5 ]; writeln(remove!(SwapStrategy.stable)(a, 1, 3)); a = [ 0, 1, 2, 3, 4, 5 ]; writeln(remove!(SwapStrategy.stable)(a, 1, tuple(3, 6))); a = [ 0, 1, 2, 3, 4, 5 ]; writeln(remove!(SwapStrategy.unstable)(a, 1)); a = [ 0, 1, 2, 3, 4, 5 ]; writeln(remove!(SwapStrategy.unstable)(a, tuple(1, 4)));

Examples:

import std.typecons : tuple;

writeln([4, 5, 6].remove(1)); writeln([4, 5, 6, 7, 8].remove(1, 3)); writeln([4, 5, 6, 7, 8].remove(tuple(1, 3))); writeln([4, 5, 6, 7, 8].remove(0, tuple(1, 3), 4));

Examples:

SwapStrategy.unstable is faster, but doesn't guarantee the same order of the original array

writeln([5, 6, 7, 8].remove!(SwapStrategy.stable)(1)); writeln([5, 6, 7, 8].remove!(SwapStrategy.unstable)(1));

Range remove(alias pred, SwapStrategy s = SwapStrategy.stable, Range)(Range range);

Reduces the length of thebidirectional range range by removing elements that satisfy pred. If s = SwapStrategy.unstable, elements are moved from the right end of the range over the elements to eliminate. If s = SwapStrategy.stable (the default), elements are moved progressively to front such that their relative order is preserved. Returns the filtered range.

Parameters:

Returns:

the range with all of the elements where pred is true removed

Examples:

static immutable base = [1, 2, 3, 2, 4, 2, 5, 2];

int[] arr = base[].dup;

writeln(remove!("a == 2")(arr)); arr[] = base[];

writeln(remove!(a => a == 2)(arr));

Range reverse(Range)(Range r)
if (isBidirectionalRange!Range && (hasSwappableElements!Range || hasAssignableElements!Range && hasLength!Range && isRandomAccessRange!Range || isNarrowString!Range && isAssignable!(ElementType!Range)));

Reverses r in-place. Performs r.length / 2 evaluations of swap. UTF sequences consisting of multiple code units are preserved properly.

Parameters:

NoteWhen passing a string with unicode modifiers on characters, such as \u0301, this function will not properly keep the position of the modifier. For example, reversing ba\u0301d ("bád") will result in d\u0301ab ("d́ab") instead ofda\u0301b ("dáb").

Examples:

int[] arr = [ 1, 2, 3 ]; writeln(arr.reverse);

Examples:

char[] arr = "hello\U00010143\u0100\U00010143".dup; writeln(arr.reverse);

Range strip(Range, E)(Range range, E element)
if (isBidirectionalRange!Range && is(typeof(range.front == element) : bool));

Range strip(alias pred, Range)(Range range)
if (isBidirectionalRange!Range && is(typeof(pred(range.back)) : bool));

Range stripLeft(Range, E)(Range range, E element)
if (isInputRange!Range && is(typeof(range.front == element) : bool));

Range stripLeft(alias pred, Range)(Range range)
if (isInputRange!Range && is(typeof(pred(range.front)) : bool));

Range stripRight(Range, E)(Range range, E element)
if (isBidirectionalRange!Range && is(typeof(range.back == element) : bool));

Range stripRight(alias pred, Range)(Range range)
if (isBidirectionalRange!Range && is(typeof(pred(range.back)) : bool));

The strip group of functions allow stripping of either leading, trailing, or both leading and trailing elements.

The stripLeft function will strip the front of the range, the stripRight function will strip the back of the range, while the strip function will strip both the front and back of the range.

Note that the strip and stripRight functions require the range to be a BidirectionalRange range.

All of these functions come in two varieties: one takes a target element, where the range will be stripped as long as this element can be found. The other takes a lambda predicate, where the range will be stripped as long as the predicate returns true.

Returns:

a Range with all of range except element at the start and end

Examples:

Strip leading and trailing elements equal to the target element.

writeln(" foobar ".strip(' ')); writeln("00223.444500".strip('0')); writeln("ëëêéüŗōpéêëë".strip('ë')); writeln([1, 1, 0, 1, 1].strip(1)); writeln([0.0, 0.01, 0.01, 0.0].strip(0).length);

Examples:

Strip leading and trailing elements while the predicate returns true.

writeln(" foobar ".strip!(a => a == ' ')()); writeln("00223.444500".strip!(a => a == '0')()); writeln("ëëêéüŗōpéêëë".strip!(a => a == 'ë')()); writeln([1, 1, 0, 1, 1].strip!(a => a == 1)()); writeln([0.0, 0.01, 0.5, 0.6, 0.01, 0.0].strip!(a => a < 0.4)().length);

Examples:

Strip leading elements equal to the target element.

writeln(" foobar ".stripLeft(' ')); writeln("00223.444500".stripLeft('0')); writeln("ůůűniçodêéé".stripLeft('ů')); writeln([1, 1, 0, 1, 1].stripLeft(1)); writeln([0.0, 0.01, 0.01, 0.0].stripLeft(0).length);

Examples:

Strip leading elements while the predicate returns true.

writeln(" foobar ".stripLeft!(a => a == ' ')()); writeln("00223.444500".stripLeft!(a => a == '0')()); writeln("ůůűniçodêéé".stripLeft!(a => a == 'ů')()); writeln([1, 1, 0, 1, 1].stripLeft!(a => a == 1)()); writeln([0.0, 0.01, 0.10, 0.5, 0.6].stripLeft!(a => a < 0.4)().length);

Examples:

Strip trailing elements equal to the target element.

writeln(" foobar ".stripRight(' ')); writeln("00223.444500".stripRight('0')); writeln("ùniçodêéé".stripRight('é')); writeln([1, 1, 0, 1, 1].stripRight(1)); writeln([0.0, 0.01, 0.01, 0.0].stripRight(0).length);

Examples:

Strip trailing elements while the predicate returns true.

writeln(" foobar ".stripRight!(a => a == ' ')()); writeln("00223.444500".stripRight!(a => a == '0')()); writeln("ùniçodêéé".stripRight!(a => a == 'é')()); writeln([1, 1, 0, 1, 1].stripRight!(a => a == 1)()); writeln([0.0, 0.01, 0.10, 0.5, 0.6].stripRight!(a => a > 0.4)().length);

void swap(T)(ref T lhs, ref T rhs)
if (is(typeof(lhs.proxySwap(rhs))));

pure nothrow @nogc @trusted void swap(T)(ref T lhs, ref T rhs)
if (isBlitAssignable!T && !is(typeof(lhs.proxySwap(rhs))));

Swaps lhs and rhs. The instances lhs and rhs are moved in memory, without ever calling opAssign, nor any other function. Tneed not be assignable at all to be swapped.

If lhs and rhs reference the same instance, then nothing is done.

lhs and rhs must be mutable. If T is a struct or union, then its fields must also all be (recursively) mutable.

Parameters:

Examples:

int a = 42, b = 34; swap(a, b); assert(a == 34 && b == 42);

static struct S { int x; char c; int[] y; } S s1 = { 0, 'z', [ 1, 2 ] }; S s2 = { 42, 'a', [ 4, 6 ] }; swap(s1, s2); writeln(s1.x); writeln(s1.c); writeln(s1.y); writeln(s2.x); writeln(s2.c); writeln(s2.y); immutable int imm1 = 1, imm2 = 2; static assert(!__traits(compiles, swap(imm1, imm2)));

int c = imm1 + 0; int d = imm2 + 0; swap(c, d); writeln(c); writeln(d);

Examples:

static struct NoCopy { this(this) { assert(0); } int n; string s; } NoCopy nc1, nc2; nc1.n = 127; nc1.s = "abc"; nc2.n = 513; nc2.s = "uvwxyz";

swap(nc1, nc2); assert(nc1.n == 513 && nc1.s == "uvwxyz"); assert(nc2.n == 127 && nc2.s == "abc");

swap(nc1, nc1); swap(nc2, nc2); assert(nc1.n == 513 && nc1.s == "uvwxyz"); assert(nc2.n == 127 && nc2.s == "abc");

static struct NoCopyHolder { NoCopy noCopy; } NoCopyHolder h1, h2; h1.noCopy.n = 31; h1.noCopy.s = "abc"; h2.noCopy.n = 65; h2.noCopy.s = null;

swap(h1, h2); assert(h1.noCopy.n == 65 && h1.noCopy.s == null); assert(h2.noCopy.n == 31 && h2.noCopy.s == "abc");

swap(h1, h1); swap(h2, h2); assert(h1.noCopy.n == 65 && h1.noCopy.s == null); assert(h2.noCopy.n == 31 && h2.noCopy.s == "abc");

const NoCopy const1, const2; assert(const1.n == 0 && const2.n == 0); static assert(!__traits(compiles, swap(const1, const2)));

void swapAt(R)(auto ref R r, size_t i1, size_t i2);

Swaps two elements in-place of a range r, specified by their indices i1 and i2.

Parameters:

Examples:

import std.algorithm.comparison : equal; auto a = [1, 2, 3]; a.swapAt(1, 2); assert(a.equal([1, 3, 2]));

Tuple!(InputRange1, InputRange2) swapRanges(InputRange1, InputRange2)(InputRange1 r1, InputRange2 r2)
if (hasSwappableElements!InputRange1 && hasSwappableElements!InputRange2 && is(ElementType!InputRange1 == ElementType!InputRange2));

Swaps all elements of r1 with successive elements in r2. Returns a tuple containing the remainder portions of r1 and r2 that were not swapped (one of them will be empty). The ranges may be of different types but must have the same element type and support swapping.

Returns:

Tuple containing the remainder portions of r1 and r2 that were not swapped

Examples:

import std.range : empty; int[] a = [ 100, 101, 102, 103 ]; int[] b = [ 0, 1, 2, 3 ]; auto c = swapRanges(a[1 .. 3], b[2 .. 4]); assert(c[0].empty && c[1].empty); writeln(a); writeln(b);

void uninitializedFill(Range, Value)(Range range, Value value)
if (isInputRange!Range && hasLvalueElements!Range && is(typeof(range.front = value)));

Initializes each element of range with value. Assumes that the elements of the range are uninitialized. This is of interest for structs that define copy constructors (for all other types, fill and uninitializedFill are equivalent).

Parameters:

Examples:

import core.stdc.stdlib : malloc, free;

auto s = (cast(int*) malloc(5 * int.sizeof))[0 .. 5]; uninitializedFill(s, 42); writeln(s); scope(exit) free(s.ptr);

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