JavaScript How to Get the First Three Characters of a String? (original) (raw)

Last Updated : 03 Dec, 2024

Here are the various methods to get the first three characters of a string in JavcaScript

1. Using String.slice() Method

The slice() method is one of the most commonly used and versatile methods to extract a part of a string. It allows you to specify the start and end positions for slicing the string.

JavaScript `

let s = 'Hello, World!'; let res = s.slice(0, 3); console.log(res);

slice(0, 3) extracts the characters starting from index 0 and up to but not including index 3.
The slice() method does not modify the original string, but returns a new string containing the sliced portion.

2. Using String.substr() Method

The substr() method is another option for extracting parts of a string. It allows you to specify the starting index and the length of the substring you want to extract.

JavaScript `

let s = 'Hello, World!'; let res = s.substr(0, 3);
console.log(res);

**substr(0, 3) starts at index 0 and extracts 3 characters from the string.
Unlike slice(), **substr() accepts the second argument as the number of characters to extract, not the end index.

3. Using String.substring() Method

The substring() method is similar to **slice(), but with slightly different behavior. It takes two arguments: the starting index and the ending index, and extracts the characters between them.

JavaScript `

let s = 'Hello, World!'; let res = s.substring(0, 3); console.log(res);

**substring(0, 3) extracts characters from index 0 to index 3 (exclusive).
**substring() behaves similarly to slice() but swaps the arguments if the first index is greater than the second.

4. Using Array.slice() with String Conversion

In JavaScript, strings can be treated as arrays of characters, so you can also use the slice() method on a string converted to an array to get the first three characters.

JavaScript `

let s = 'Hello, World!'; let res = [...s].slice(0, 3).join(''); console.log(res);

The **[...str] syntax converts the string into an array of characters.
**slice(0, 3) slices the first three characters, and join('') joins the array back into a string.

5. Using String Indexing with a Loop

If you want to manually retrieve the first three characters, you can iterate over the string and extract the characters at the specific indexes.

JavaScript `

let s = 'Hello, World!'; let res = ''; for (let i = 0; i < 3; i++) { res += s[i]; } console.log(res);

The loop iterates over the string from index 0 to 2 and concatenates the characters into a new string.
While this method works, it is less efficient and more verbose than the other approaches.

Which Approach to Choose?

**Method	**When to Use	**Why Choose It
**slice()	For most common cases when you need a simple and efficient solution.	Simple and widely used for string slicing.
**substr()	When you prefer to specify the length of the substring instead of the end index.	Good for scenarios where the length of the substring is more important than the end index.
**substring()	When you need a method similar to slice(), but with different handling of arguments.	Slightly less common than slice(), but still widely used.
**Array.slice() with String Conversion	When you want to treat the string as an array and need more flexibility.	More complex and less efficient, but can be useful for array-like operations.
**Looping with String Indexing	When you want to manually control each character in the string.	Least efficient, but useful for custom scenarios.