3v4l.org

run code in 300+ PHP versions simultaneously
<?php echo preg_match('/Я/ui', 'я'); echo preg_match('/(?=Я)/ui', 'я'); echo preg_match('/Л/ui', 'л'); echo preg_match('/(?=Л)/ui', 'л');

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78.46 ms | 407 KiB | 5 Q