string.split

The split() method splits a String object into an array of strings by separating the string into substrings, using a specified separator string to determine where to make each split.

Syntax

str.split([separator[, limit]])

Parameters

separator Optional

Specifies the string which denotes the points at which each split should occur. The separator is treated as a string or as a regular expression. If a plain-text separator contains more than one character, that entire string must be found to represent a split point. If separator is omitted or does not occur in str, the array returned contains one element consisting of the entire string. If separator is an empty string, str is converted to an array of characters.

limit Optional

Integer specifying a limit on the number of splits to be found. When this parameter is provided, the split() method splits the string at each occurence of the specified separator but stops when limit entries have been placed into the array. It may still contain fewer entries than limit if the end of the string is reached before the specified limit is reached. The left-over text is not returned in the new array.

Return value

An Array of strings split at each point where the separator occurs in the given string.

Description

When found, separator is removed from the string and the substrings are returned in an array. If separator is not found or is omitted, the array contains one element consisting of the entire string. If separator is an empty string, str is converted to an array of characters. If separator appears at the beginning or end of the string, or both, the array begins, ends, or both begins and ends, respectively, with an empty string. Thus, if the string consists solely of one instance of separator, the array consists of two empty strings.

If separator is a regular expression that contains capturing parentheses, then each time separator is matched, the results (including any undefined results) of the capturing parentheses are spliced into the output array. However, not all browsers support this capability.

Examples

Using split()

The following example defines a function that splits a string into an array of strings using the specified separator. After splitting the string, the function logs messages indicating the original string (before the split), the separator used, the number of elements in the array, and the individual array elements.

function splitString(stringToSplit, separator) {
  var arrayOfStrings = stringToSplit.split(separator);

  console.log('The original string is: "' + stringToSplit + '"');
  console.log('The separator is: "' + separator + '"');
  console.log('The array has ' + arrayOfStrings.length + ' elements: ' + arrayOfStrings.join(' / '));
}

var tempestString = 'Oh brave new world that has such people in it.';
var monthString = 'Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec';

var space = ' ';
var comma = ',';

splitString(tempestString, space);
splitString(tempestString);
splitString(monthString, comma);

This example produces the following output:

The original string is: "Oh brave new world that has such people in it."
The separator is: " "
The array has 10 elements: Oh / brave / new / world / that / has / such / people / in / it.

The original string is: "Oh brave new world that has such people in it."
The separator is: "undefined"
The array has 1 elements: Oh brave new world that has such people in it.

The original string is: "Jan,Feb,Mar,Apr,May,Jun,Jul,Aug,Sep,Oct,Nov,Dec"
The separator is: ","
The array has 12 elements: Jan / Feb / Mar / Apr / May / Jun / Jul / Aug / Sep / Oct / Nov / Dec

Removing spaces from a string

In the following example, split() looks for 0 or more spaces followed by a semicolon followed by 0 or more spaces and, when found, removes the spaces and the semicolon from the string. nameList is the array returned as a result of split().

var names = 'Harry Trump ;Fred Barney; Helen Rigby ; Bill Abel ;Chris Hand ';

console.log(names);

var re = /\s*;\s*/;
var nameList = names.split(re);

console.log(nameList);

This logs two lines; the first line logs the original string, and the second line logs the resulting array.

Harry Trump ;Fred Barney; Helen Rigby ; Bill Abel ;Chris Hand
[ "Harry Trump", "Fred Barney", "Helen Rigby", "Bill Abel", "Chris Hand " ]

Returning a limited number of splits

In the following example, split() looks for spaces in a string and returns the first 3 splits that it finds.

var myString = 'Hello World. How are you doing?';
var splits = myString.split(' ', 3);

console.log(splits);

This script displays the following:

["Hello", "World.", "How"]

Capturing parentheses

If separator contains capturing parentheses, matched results are returned in the array.

var myString = 'Hello 1 word. Sentence number 2.';
var splits = myString.split(/(\d)/);

console.log(splits);

This script displays the following:

[ "Hello ", "1", " word. Sentence number ", "2", "." ]

Reversing a String using split()

var str = 'asdfghjkl';
var strReverse = str.split('').reverse().join(''); // 'lkjhgfdsa'
// split() returns an array on which reverse() and join() can be applied

Bonus: use === operator to test if the original string was palindrome.

Specifications

Browser compatibility

See also

• String.prototype.charAt()
• String.prototype.indexOf()
• String.prototype.lastIndexOf()
• Array.prototype.join()