请教 写个正则表达式

Question

$a = '{"17":0,"09":1,"15":1,"13":0,"16":1,"12":0,"11":0,"10":0,"14":0}';
把09，15，16从里面挑出来，即:1的前面数字挑出来谢谢

Answer 1

$a = '{"17":0,"09":1,"15":1,"13":0,"16":1,"12":0,"11":0,"10":0,"14":0}';
preg_match_all('/\d+(?=":1)/', $a, $m);
print_r($m);Array
(
    [0] => Array
        (
            [0] => 09
            [1] => 15
            [2] => 16
        ))