How to Split on Last Occurrence of Delimiter in PHP ?

Given a string, the task is to split the string based on the last occurrence of a delimiter. In this article, we use the delimiter pipe symbol i.e. “|”.

Consider the below example:

Input: 
Sam|is|working|hard

Output: 
String 1: Sam|is|working
String 2: hard

There are four approaches to split the string, which are described below:

Using strrpos() and substr() functions

The strrpos() function is used to find the position of the last occurrence of the delimiter ‘|’. If the delimiter is found ($lastDelimiterPos is not false), substr() function is then used to split the string into two parts based on the position of the last delimiter.

Example:

PHP

<?php

$string = "Sam/is/working/hard";

// Find the last occurrence of the
// delimiter '|'
$lastDelimiterPos = strrpos($string, '/');

// Check if the delimiter is found
if ($lastDelimiterPos !== false) {

    // Split the string based on the last
      // occurrence of the delimiter
    $part1 = substr($string, 0, $lastDelimiterPos);
    $part2 = substr($string, $lastDelimiterPos + 1);

    echo "String 1: $part1\n";
    echo "String 2: $part2\n";
} else {

    // Handle the case where the delimiter is not found
    echo "Delimiter not found in the string.\n";
}

?>

Output

String 1: Sam/is/working
String 2: hard

Using explode() and implode() functions

We can reverse the string and use explode() function to split the string based on the first occurrence of the delimiter, and then reverse the resulting array using implode() function.

Example:

PHP

<?php

$string = "    Sam/is/working/hard";

// Reverse the string
$reversedString = strrev($string);

// Split the reversed string based
// on the first occurrence of '|'
$parts = explode('/', $reversedString, 2);

// Reverse each part back to the
// original order
$part1 = strrev($parts[1]);
$part2 = strrev($parts[0]);

echo "String 1: $part1\n";
echo "String 2: $part2\n";

?>

Output

String 1:     Sam/is/working
String 2: hard

Using Regular Expressions

Regular expressions can be used to match the last occurrence of the delimiter and split the string accordingly.

Example:

PHP

<?php

$string = "Sam/is/working/hard";

// Match the last occurrence of '|'
preg_match('/^(.*)\/(.*)$/', $string, $matches);

// Extract the parts
$part1 = $matches[1];
$part2 = $matches[2];

echo "String 1: $part1\n";
echo "String 2: $part2\n";

?>

Output

String 1: Sam/is/working
String 2: hard

Using strrev() and strpos() Functions

Reverse the string with strrev() function and find the position of the first occurrence of the delimiter using strpos() function, and then split the reversed string.

Example:

PHP

<?php

$string = "Sam/is/working/hard";

// Reverse the string
$reversedString = strrev($string);

// Find the position of the first occurrence of '|'
$firstDelimiterPos = strpos($reversedString, "/");

// Split the reversed string based
// on the first occurrence of '|'
$part1 = substr($reversedString, $firstDelimiterPos);
$part2 = substr($reversedString, 0, $firstDelimiterPos);

// Reverse each part back to the original order
$part1 = strrev($part1);
$part2 = strrev($part2);

echo "String 1: $part1\n";
echo "String 2: $part2\n";

?>

Output

String 1: Sam/is/working/
String 2: hard