1--TEST-- 2preg_replace() 3--FILE-- 4<?php 5 6var_dump(preg_replace('{{\D+}}', 'x', '{abcd}')); 7var_dump(preg_replace('{{\D+}}', 'ddd', 'abcd')); 8 9var_dump(preg_replace('/(ab)(c)(d)(e)(f)(g)(h)(i)(j)(k)/', 'a${1}2$103', 'zabcdefghijkl')); 10 11?> 12--EXPECT-- 13string(1) "x" 14string(4) "abcd" 15string(8) "zaab2k3l" 16