Online PHP editor | refs for gWdIF

<?php function replaceStrAt($str, $substr, $from, $to = null){ is_null($to) and $to = $from; return mb_substr($str, 0, $from) . $substr . mb_substr($str, $to + 1); } function insertSubstrInto($str, $substr, $index){ return mb_substr($str, 0, $index) . $substr . mb_substr($str, $index); } $s = 'И просто текст'; echo replaceStrAt($s, "\t", 4), "\n"; echo insertSubstrInto($s, "\t", 4), "\n";