How to Explode Arrays from Right to Left: Splitting on the Last Delimiter in PHP

Exploding Arrays from Right to Left: Last Delimiter Split

In PHP, the explode() function is commonly used for splitting strings based on specified delimiters. However, if you need to split a string only on the last occurrence of a particular delimiter, you may encounter ambiguity.

For instance, consider the following scenario:

<code class="php">$split_point = ' - ';
$string = 'this is my - string - and more';</code>

If you were to use explode() directly on this string, you would get the following result:

<code class="php">$item[0] = 'this is my';
$item[1] = 'string - and more';</code>

However, this is not the desired output because we only want to split on the second instance of the delimiter. To achieve that, we can employ a slightly different approach using the strrev() function.

<code class="php">$split_point = ' - ';
$string = 'this is my - string - and more';

$result = array_map('strrev', explode($split_point, strrev($string)));</code>

Here's how this works:

1. We first reverse the entire string using strrev().
2. Then, we perform the explode() operation on the reversed string, effectively splitting it from right to left.
3. Finally, we apply strrev() again to each element of the resulting array to restore their original order.

This approach yields the following output:

<code class="php">array (
  0 => 'and more',
  1 => 'string',
  2 => 'this is my',
)</code>

By reversing the string and then splitting, we essentially transform the search into a left-to-right operation from the end of the string, allowing us to capture the last instance of the delimiter.

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