How to replace string in PHP

String is a collection of characters. You can replace string using str_replace() function. It is a PHP built in function.

In this article, I’m going to replace a string with another by using the PHP built-in str_replace() function. I putted here some useful examples and brief discussion.

Syntax:

str_replace(substring, replaced_string, original_string);

We need to provide three parameters.

Sub-string: substring is the string present in the original string that should be replaced

Replaced string: replaced_string is the new string that replaces the substring.

Original_string: original_string is the input string.

Count: This is an optional parameter to show the number of replacements

You can use PHP variable in the placement of parameters.

Example and discussion: Replace string in PHP

The examples below showing different application to make string replacement.

Example 1: Replaces a string with another string

<?php
 
//input string
$string = "I like coffee.";
 
//replacing string
$replace = str_replace("coffee","tea",$string);
 
//showing result
echo $replace;
 
?>

Output:

I like tea.

Example 2: Replace string with empty string

<?php
 
//input string
$string = "I like coffee.";
 
//replacing string
$replace = str_replace("coffee","",$string);
 
//showing result
echo $replace;
 
?>

Output:

I like .

Example 3: Replace string with integer

<?php
//input string
$string = "I like coffee.";
 
//replacing string
$replace = str_replace("coffee","2",$string);
 
//showing result
echo $replace;
 
?>

Output:

I like 2.

Note: This function is case-sensitive. You can use the str_ireplace() function to perform a case-insensitive search.

Example 5: Case insensetive replacement

<?php
echo str_replace("coffee","tea","I like Coffee.");
?>

This will result no replacement due to case sensitiveness. You need to follow the code below instead.

<?php
echo str_ireplace("coffee","tea","I like Coffee.");
?>

This will replace the string.

Example 6: Replace multiple words using array

<?php
 
//input string
$str = "I like pink, blue, and red colour";
 
//words to replace
$arr = array("blue","red","green","yellow");
 
//after replacing the words
$new = array("blue1","red1","green1","yellow1");
 
//replacing multiple words
$replace = str_replace($arr,$new,$str,$i);
 
//showing result
echo $replace.'<br>';
 
//showing the number of occurences
echo 'Total replacement '.$i;?>

Output:

I like pink, blue1, and red1 colour

Total replacement 2