PHP Manual: Tokenize string

Description

stringfalse strtok(string $string, string $token)

Alternative signature (not supported with named arguments):

stringfalse strtok(string $token)

strtok splits a string (string) into smaller strings (tokens), with each token being delimited by any character from token. That is, if you have a string like "This is an example string" you could tokenize this string into its individual words by using the space character as the token.

Note that only the first call to strtok uses the string argument. Every subsequent call to strtok only needs the token to use, as it keeps track of where it is in the current string. To start over, or to tokenize a new string you simply call strtok with the string argument again to initialize it. Note that you may put multiple tokens in the token parameter. The string will be tokenized when any one of the characters in the token argument is found.

Note:
This function behaves slightly different from what one may expect being familiar with explode. First, a sequence of two or more contiguous token characters in the parsed string is considered to be a single delimiter. Also, a token situated at the start or end of the string is ignored. For example, if a string ";aaa;;bbb;" is used, successive calls to strtok with ";" as a token would return strings "aaa" and "bbb", and then false. As a result, the string will be split into only two elements, while explode(";", $string) would return an array of 5 elements.

Parameters

string: The string being split up into smaller strings (tokens).
token: The delimiter used when splitting up string.

Return Values

A string token, or false if no more tokens are available.

Changelog

Version	Description
8.3.0	Now emits `E_WARNING` when `token` is not provided.

Examples

Example #1 strtok example

<?php
$string = "This is\tan example\nstring";
/* Use tab and newline as tokenizing characters as well  */
$tok = strtok($string, " \n\t");

while ($tok !== false) {
    echo "Word=$tok<br />";
    $tok = strtok(" \n\t");
}
?>

Example #2 strtok behavior on empty part found

<?php
$first_token  = strtok('/something', '/');
$second_token = strtok('/');
var_dump($first_token, $second_token);
?>

The above example will output:

    string(9) "something"
    bool(false)

Example #3 The difference between strtok and explode

<?php
$string = ";aaa;;bbb;";

$parts = [];
$tok = strtok($string, ";");
while ($tok !== false) {
    $parts[] = $tok;
    $tok = strtok(";");
}
echo json_encode($parts),"\n";

$parts = explode(";", $string);
echo json_encode($parts),"\n";

The above example will output:

["aaa","bbb"]
["","aaa","","bbb",""]

Notes

Warning

This function may return Boolean false, but may also return a non-Boolean value which evaluates to false. Please read the section on Booleans for more information. Use the === operator for testing the return value of this function.

strtok