How to Split a String, Breaking At a Particular Character

How do I split a string, breaking at a particular character?

With JavaScript’s String.prototype.split function:

var input = 'john smith~123 Street~Apt 4~New York~NY~12345';

var fields = input.split('~');

var name = fields[0];
var street = fields[1];
// etc.

How to split string with character \ - Javascript

Backslashes '\' escape the next character in the sequence. If you need the '\' in the string, your string will need to look like '\\op*Bw'

let s = '\\op*Bw'.split('');
console.log(s) // ['\', 'o', 'p', '*', 'B', 'w']

How to split a string at a specific character but not replace that character?

You can use Lookahead and Lookbehind Zero-Length Assertions.

Example:

// string
$str = "abc;def;ghi{jkl;}if('mno') {pqr;}";
// expression
$pattern = "/(?=[;{\(])/";

$result = preg_split($pattern, $str);

$result is a array like

array (
  0 => "abc",
  1 => ";def",
  2 => ";ghi",
  3 => "{jkl",
  4 => ";}if",
  5 => "('mno') ",
  6 => "{pqr",
  7 => ";}",
)

How do I split a string in Java?

Use the appropriately named method String#split().

String string = "004-034556";
String[] parts = string.split("-");
String part1 = parts[0]; // 004
String part2 = parts[1]; // 034556

Note that split's argument is assumed to be a regular expression, so remember to escape special characters if necessary.

there are 12 characters with special meanings: the backslash \, the caret ^, the dollar sign $, the period or dot ., the vertical bar or pipe symbol |, the question mark ?, the asterisk or star *, the plus sign +, the opening parenthesis (, the closing parenthesis ), and the opening square bracket [, the opening curly brace {, These special characters are often called "metacharacters".

For instance, to split on a period/dot . (which means "any character" in regex), use either backslash \ to escape the individual special character like so split("\\."), or use character class [] to represent literal character(s) like so split("[.]"), or use Pattern#quote() to escape the entire string like so split(Pattern.quote(".")).

String[] parts = string.split(Pattern.quote(".")); // Split on the exact string.

To test beforehand if the string contains certain character(s), just use String#contains().

if (string.contains("-")) {
    // Split it.
} else {
    throw new IllegalArgumentException("String " + string + " does not contain -");
}

Note, this does not take a regular expression. For that, use String#matches() instead.

If you'd like to retain the split character in the resulting parts, then make use of positive lookaround. In case you want to have the split character to end up in left hand side, use positive lookbehind by prefixing ?<= group on the pattern.

String string = "004-034556";
String[] parts = string.split("(?<=-)");
String part1 = parts[0]; // 004-
String part2 = parts[1]; // 034556

In case you want to have the split character to end up in right hand side, use positive lookahead by prefixing ?= group on the pattern.

String string = "004-034556";
String[] parts = string.split("(?=-)");
String part1 = parts[0]; // 004
String part2 = parts[1]; // -034556

If you'd like to limit the number of resulting parts, then you can supply the desired number as 2nd argument of split() method.

String string = "004-034556-42";
String[] parts = string.split("-", 2);
String part1 = parts[0]; // 004
String part2 = parts[1]; // 034556-42

split string only on first instance of specified character

Use capturing parentheses:

'good_luck_buddy'.split(/_(.*)/s)
['good', 'luck_buddy', ''] // ignore the third element

They are defined as

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

So in this case we want to split at _.* (i.e. split separator being a sub string starting with _) but also let the result contain some part of our separator (i.e. everything after _).

In this example our separator (matching _(.*)) is _luck_buddy and the captured group (within the separator) is lucky_buddy. Without the capturing parenthesis the luck_buddy (matching .*) would've not been included in the result array as it is the case with simple split that separators are not included in the result.

We use the s regex flag to make . match on newline (\n) characters as well, otherwise it would only split to the first newline.

How to split a string by a specific character?

var myString = "0001-102525";
var splitString = myString.Split("-");

Then access either like so:

splitString[0] and splitString[1]

Don't forget to check the count/length if you are splitting user inputted strings as they may not have entered the '-' which would cause an OutOfRangeException.

How do I split a string into an array of characters?

You can split on an empty string:

var chars = "overpopulation".split('');

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If you just want to access a string in an array-like fashion, you can do that without split:

var s = "overpopulation";
for (var i = 0; i < s.length; i++) {
    console.log(s.charAt(i));
}

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You can also access each character with its index using normal array syntax. Note, however, that strings are immutable, which means you can't set the value of a character using this method, and that it isn't supported by IE7 (if that still matters to you).

var s = "overpopulation";

console.log(s[3]); // logs 'r'

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