PHP Manual: Case-insensitive strstr

Description

stringfalse stristr(string $haystack, string $needle, bool $before_needle = false)

Returns all of haystack starting from and including the first occurrence of needle to the end.

Parameters

haystack

The string to search in

needle

The string to search for.

Prior to PHP 8.0.0, if needle is not a string, it is converted to an integer and applied as the ordinal value of a character. This behavior is deprecated as of PHP 7.3.0, and relying on it is highly discouraged. Depending on the intended behavior, the needle should either be explicitly cast to string, or an explicit call to chr should be performed.

before_needle

If true, stristr returns the part of the haystack before the first occurrence of the needle (excluding needle).

needle and haystack are examined in a case-insensitive manner.

Return Values

Returns the matched substring. If needle is not found, returns false.

Changelog

Version	Description
8.2.0	Case folding no longer depends on the locale set with setlocale. Only ASCII case folding will be done. Non-ASCII bytes will be compared by their byte value.
8.0.0	`needle` now accepts an empty string.
8.0.0	Passing an int as `needle` is no longer supported.
7.3.0	Passing an int as `needle` has been deprecated.

Examples

Example #1 stristr example

<?php
  $email = 'USER@EXAMPLE.com';
  echo stristr($email, 'e'); // outputs ER@EXAMPLE.com
  echo stristr($email, 'e', true); // outputs US
?>

Example #2 Testing if a string is found or not

<?php
  $string = 'Hello World!';
  if(stristr($string, 'earth') === FALSE) {
    echo '"earth" not found in string';
  }
// outputs: "earth" not found in string
?>

Example #3 Using a non "string" needle

<?php
  $string = 'APPLE';
  echo stristr($string, 97); // 97 = lowercase a
// outputs: APPLE
?>

Notes

Note: This function is binary-safe.

stristr