How to check if a string contains a substring

Short answer

str_contains() returns true when the substring is found:

<?php
 
var_dump(str_contains('Hello, world', 'world'));

Output:

bool(true)

Case-insensitive search

The search is case-sensitive. To ignore case, convert both strings to lowercase with mb_strtolower():

<?php
 
$text = 'Hello, World';
 
var_dump(str_contains(mb_strtolower($text), mb_strtolower('WORLD')));

Output:

bool(true)

Finding the position

If you need to know where the substring is, use mb_strpos(). It returns the position or false:

<?php
 
var_dump(mb_strpos('Hello, world', 'world'));

Output:

int(7)