How to Replace String in PHP
This article will introduce a method to replace part of a string in PHP.
Use the str_replace() Function to Replace Part of a String in PHP
In PHP, the specialized function to replace a part of a string is str_replace(). This function searches the given substring and replaces it with the provided value. The correct syntax to use this function is as follows.
str_replace($search, $replace, $subject, $count);
The str_replace() function has only four parameters. The details of its parameters are as follows.
| Variables | Description | |
|---|---|---|
$search |
mandatory | It is the string or an array that we want to search in the given string or array. This $search string or array is then replaced by the given $replace parameter. |
$replace |
mandatory | It is the string or array that will be placed on the $search position. |
$subject |
mandatory | It is the string or array whose substring will be searched and replaced. |
$count |
optional | If given, it counts the replacements performed. |
This function returns the modified string or array. The program below shows how we can use the str_replace() function to replace part of a string in PHP.
<?php
$mystring = "This is my string.";
echo("This is the string before replacement: ");
echo($mystring);
echo("\n");
$mynewstring = str_replace(" my ", " ", $mystring);
echo("Now, this is the string after replacement: ");
echo($mynewstring);
?>
Output:
This is the string before replacement: This is my string.
Now, this is the string after replacement: This is string.
The function has returned the modified string.
Now, if we pass the $count parameter then it will count the replacements made.
<?php
$mystring = "This is my string.";
echo("This is the string before replacement: ");
echo($mystring);
echo("\n");
$mynewstring = str_replace(" my ", " ", $mystring, $count);
echo("Now, this is the string after replacement: ");
echo($mynewstring);
echo("\n");
echo("The number of replacements is: ");
echo($count);
?>
Output:
This is the string before replacement: This is my string.
Now, this is the string after replacement: This is string.
The number of replacements is: 1
The output shows that the function makes only one replacement. It means that the $search string only appeared one time in the passed string.