PHP String stristr() Function

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The PHP String stristr() function is a built-in function. It searches for the first occurrence of a string within another string. And it shows the portion of the latter beginning with the first occurrence of the first in the latter (if given). This function is case insensitive.

Syntax

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

string stristr ( string $string, 
   string $search, 
   bool $before_search = false 
)

Parameters

Here are the parameters of the stristr() function −

• $string − (Required) It is used to specify the string to search.

• $search − (Required) It is used to specify the string to search for.

• $before_search − (Optional) A boolean value with a default value of "false". When set to "true", it returns the section of the string before the first occurrence of the search parameter.

Return Value

The stristr() function returns the remainder of the string (from the matching point), or FALSE if the string to be searched for was not found.

PHP Version

First introduced in core PHP 4, the stristr() function continues to function easily in PHP 5, PHP 7, and PHP 8.

Example 1

First we will show you the basic example of the PHP String stristr() function.

<?php
   echo stristr("Hello Tutorialspoint!", "p"); 
?>

Output

Here is the outcome of the following code −

point!

Example 2

In the below PHP code, we will use the stristr() function and find the first occurrence of a case-insensitive substring in the given string.

<?php
   // Search for a case-insensitive substring
   $string = "Hello World!";
   $search = "world";

   $result = stristr($string, $search);

   if ($result !== false) {
      echo "Found: $result"; 
   } else {
      echo "Not found!";
   }
?> 

Output

This will generate the below output −

Found: World!

Example 3

This example shows that the function stristr() works even when the substring is not in the same case as the main string.

<?php
   // Demonstrating case-insensitivity
   $string = "Learning PHP is Fun!";
   $search = "php";

   $result = stristr($string, $search);

   if ($result !== false) {
      echo "Found: $result"; 
   } else {
      echo "Not found!";
   }
?> 

Output

This will create the below output −

Found: PHP is Fun!

Example 4

This PHP program shows how to use stristr() function to return the part of the string that comes before the first occurrence of the substring.

<?php
   // Using the before_search parameter
   $string = "Programming with PHP is enjoyable.";
   $search = "PHP";

   // true for before_search
   $result = stristr($string, $search, true); 

   if ($result !== false) {
      echo "Before '$search': $result"; 
   } else {
      echo "Not found!";
   }
?> 

Output

Following is the output of the above code −

Before 'PHP': Programming with