PHP strripos() Function: Syntax, Parameters, Return Value, and Usage Examples

The strripos() function in PHP finds the position of the last occurrence of a substring within a string without case sensitivity, similar to strpos() but case‑insensitive.

strripos() Function Syntax

int strripos ( string $haystack , string $needle [, int $offset = 0 ] )

Parameters: $haystack: The string to be searched. $needle: The substring to look for. $offset (optional): The position in the string to start searching from; default is 0.

The function returns the position of the last occurrence of $needle in $haystack, or false if the substring is not found.

strripos() Function Usage Examples

Example 1: Find the last occurrence of a character

$str = "Hello World";
$pos = strripos($str, "o");
echo $pos; // outputs 7

This searches for the last "o" in $str, storing the position (7) in $pos and printing it.

Example 2: Find the last occurrence with a starting offset

$str = "Hello World";
$pos = strripos($str, "o", 5);
echo $pos; // outputs 4

Starting the search at position 5, the last "o" is found at index 4.

Example 3: Case‑insensitive search

$str = "Hello World";
$pos = strripos($str, "WORLD");
echo $pos; // outputs 6

Because strripos() ignores case, the substring "WORLD" is found at position 6.

Example 4: Substring not found

$str = "Hello World";
$pos = strripos($str, "X");
var_dump($pos); // outputs bool(false)

If the substring does not exist, the function returns false.

Summary

The article provides a comprehensive guide to the PHP strripos() function, explaining its purpose, syntax, parameters, return values, and offering practical examples for common use cases such as reverse searching, offset handling, and case‑insensitive matching.

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