PHP explode(): Split a String by a Separator into an Array of Strings

Summary: in this tutorial, you’ll learn how to use the PHP explode() function to split a string by a separator into an array of strings.

Introduction to the PHP explode() function #

The PHP explode() function returns an array of strings by splitting a string by a separator. The following shows the syntax of the explode() function:

explode ( string $separator , string $string , int $limit = PHP_INT_MAX ) : array

The explode() function has the following parameters:

$separator is the delimiter that the explode() function uses to split the $string.
$string is the input string
$limit specifies how the function will return the result array.

If the $limit is positive, the explode() function returns an array with $limit elements where the last element containing the rest of the string.

If the $limit is zero, explode() function interprets it as one. So the function returns an array with the original string.

If the $limit is negative, the explode() function splits the $string using the $separator. Also, it removes the last $limit elements from the result array.

Prior to PHP 8.0.0, the explode() function returns false if the $separator is an empty string. Starting from PHP 8.0.0, the explode() function throws a ValueError instead.

PHP explode() function examples #

Let’s take some examples of using the explode() function.

1) Simple the PHP explode() function example #

The following example uses the explode() function to split a string by a comma (,):

<?php

$str = 'first_name,last_name,email,phone';
$headers = explode(',', $str);

print_r($headers);

Try it

Output:

array(4) 
{ 
    [0]=> string(10) "first_name" 
    [1]=> string(9) "last_name" 
    [2]=> string(5) "email" 
    [3]=> string(5) "phone" 
}

2) Using the PHP explode() function with a positive $limit #

The following example uses the explode() function with the a positive $limit argument:

$str = 'first_name,last_name,email,phone';
$headers = explode(',', $str, 3);

var_dump($headers);

Try it

Output:

array(3) 
{ 
    [0]=> string(10) "first_name" 
    [1]=> string(9) "last_name" 
    [2]=> string(5) "email,phone" 
}

As shown clearly in the output, the returned array contains three elements specified by the $limit argument. Also, the last element has the remaining string.

3) Using the PHP explode() function with a negative $limit #

The following example uses the explode() function with the a negative $limit argument:

<?php

$str = 'first_name,last_name,email,phone';
$headers = explode(',', $str, -1);

var_dump($headers);

Try it

Output:

array(3) 
{ 
    [0]=> string(10) "first_name" 
    [1]=> string(9) "last_name" 
    [2]=> string(5) "email" 
}

In this example, the explode() function returns an array of the string split by the comma (,). Also, it excludes the last element from the result array.

If you use -2 instead of –1 for the $limit, the explode() function will remove the last 2 elements. For example:

<?php

$str = 'first_name,last_name,email,phone';
$headers = explode(',', $str, -1);

var_dump($headers);

Try it

Output:

array(2) 
{ 
    [0]=> string(10) "first_name" 
    [1]=> string(9) "last_name"
}

4) A practical example of the PHP explode() function #

The following str_after() function returns the remainder of a string after the first occurrence of a string:

<?php

function str_after($str, $search)
{
    return $search === '' ? $str : array_reverse(explode($search, $str, 2))[0];
}

How it works.

First, split the string into an array of two elements separated by the $search string.
Second, reverse the result array and return the first element of the result array.

The following example uses the str_after() function to get the domain name part of an email:

<?php
// ...

echo str_after('[email protected]', '@');

Try it

Output:

phptutorial.net

Summary #

Use the PHP explode() function to return an array of strings by splitting a string by a separator.

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