Remove a SubString from a String in PHP

This article, will discuss multiple ways to remove a substring from a string in PHP.

Table Of Contents

Background

Removing a specific substring from a string is a common task in PHP, often necessary for data cleaning, formatting text, or manipulating user input. For example, if you have the following string:

$originalString = "Hello, this is a sample string";

And you want to remove the substring “sample ” from it, the expected output would be:

"Hello, this is a string"

Let’s look at some methods to accomplish this.

Solution 1: Using str_replace()

The str_replace() function is used to replace all occurrences of a search string in a string with a replacement string. In this case, you can use it to replace the target substring with an empty string.

Let’s see the complete example,

<?php
$originalString = "Hello, this is a sample string";
$substringToRemove = "sample ";

// Remove the substring
$modifiedString = str_replace($substringToRemove, '', $originalString);

echo $modifiedString;
?>

Output

Hello, this is a string

In this code:
– We are replacing the $substringToRemove (which is “sample “) in $originalString with an empty string (”).
– str_replace() will remove all occurrences of the specified substring, resulting in a string without the target substring.

Solution 2: Using preg_replace()

For more complex substring removals that might involve patterns or special conditions, preg_replace() can be used. This function performs a regular expression search and replace.

Let’s say you want to remove a substring that follows a certain pattern, e.g., removing any numbers within brackets.

Let’s see the complete example,

<?php
$originalString = "This is a string with a number [1234] in it";
$pattern = '/[d+]/'; // Pattern to match numbers within brackets

// Remove the substring matching the pattern
$modifiedString = preg_replace($pattern, '', $originalString);

echo $modifiedString;
?>

Output

This is a string with a number  in it

In this code:
– $pattern is a regular expression that matches numbers within square brackets.
– preg_replace($pattern, ”, $originalString) replaces the matched pattern with an empty string.
– This method is useful for removing substrings that follow a specific pattern.

Summary

To remove a substring from a string in PHP, str_replace() is a straightforward method for simple substring removals, while preg_replace() is more suitable for pattern-based removals. Both methods offer flexibility and effectiveness for different substring manipulation scenarios.