PHP String str_ireplace Function

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The PHP String str_ireplace() function can be used to replace all instances of a word or text in a string or array, ignoring capital and lowercase letter differences. If you want to replace text based on a pattern (e.g. matching specific formats), use the preg_replace function with the "i" option for case-insensitive matching.

Syntax

Below is the syntax of the PHP String str_ireplace() function −

string|array str_ireplace(
   array|string $search,
   array|string $replace,
   string|array $subject,
   int &$count = null
)

Parameters

Here are the parameters of the str_ireplace() function −

• $search − (Required) It is the value searched for, also known as the needle. An array can be used to represent many needles.

• $replace − (Required) It is the the value that substitutes the found search results. An array can be used to provide several replacements.

• $subject − (Required) It is the the text or array being searched and replaced, also known as the haystack. If the subject is an array, the search and replace is executed on each element of the array, and the return value is also an array.

• $count − (Optional) If passed, this value will be set to the number of replacements executed.

Return Value

The str_ireplace() function returns different values depending on whether or not the $option parameter is used. And FALSE on failure.

PHP Version

First introduced in core PHP 5, the str_ireplace() function continues to function easily in PHP 7, and PHP 8.

Example 1

Here is the basic example of the PHP String str_ireplace() function to replace a single word in the given string. In our example the word "world" will be replaced with "PHP". The case (uppercase or lowercase) does not matter.

<?php
   $string = "Hello World!";
   $result = str_ireplace("world", "PHP", $string);

   echo $result;
?>

Output

Here is the outcome of the following code −

Hello PHP!

Example 2

In the below PHP code we will try to use the str_ireplace() function and replace multiple words in a string at once with the help of an arrays.

<?php
   $string = "Learn JavaScript, HTML, and CSS.";
   $search = ["javascript", "html", "css"];
   $replace = ["PHP", "MySQL", "Bootstrap"];

   $result = str_ireplace($search, $replace, $string);

   echo $result; 
?> 

Output

This will generate the below output −

Learn PHP, MySQL, and Bootstrap.

Example 3

Now the below code we are using str_ireplace() function and count how many replacements were made using this function and prints it.

<?php
   $string = "PHP is great. I love PHP!";
   $search = "php";
   $replace = "Python";
   $replaceCount = 0;

   $result = str_ireplace($search, $replace, $string, $replaceCount);

   echo $result;
   echo "\nReplacements: " . $replaceCount;
?> 

Output

This will create the below output −

Python is great. I love Python!
Replacements: 2

Example 4

In the following example, we are using the str_ireplace() function to replace specific words in an HTML string without affecting the tags.

<?php
   $htmlContent = "<h1>Welcome to the blog><p>Enjoy exploring the website!</p>";
   $search = "blog";
   $replace = "Tutorialspoint";

   $result = str_ireplace($search, $replace, $htmlContent);

   echo $result;
?> 

Output

Following is the output of the above code −

<h1>Welcome to the Tutorialspoint</h1><p>Enjoy exploring the website!</p>