如何编写在 $_POST['some_string'] 之后删除所有内容的正则表达式

Question

我有以下字符串：string = '$_POST["a_string_of_unspecified_length"][4]input&set1';如何编写一个仅返回$_POST["a_string_of_unspecified-length"]并丢弃第一组括号后的所有内容的正则表达式$string_afer_regex = '$_POST["a_string_of_unspecified_length"]'

Answer 1

使用正则表达式 ^\$_POST\[[^]]+\]

$str = '$_POST["a_string_of_unspecified_length"][4]input&set1';

preg_match('~^\$_POST\[[^]]+\]~', $str, $matches);

print_R($matches);

// $_POST["a_string_of_unspecified_length"]

^     - beginning of string

\$    - escaped dollar sign

_POST - normal characters, just part of string

\[    - escaped '['

[^]]+ - everything till ']', + means 'more than 1 character'

\]    - escaped '['

the rest doesn't care us, there can be whatever

如果需要，没有正则表达式

$str = '$_POST["a_string_of_unspecified_length"][4]input&set1';

echo substr($str, 0, strpos($str, ']') + 1);

// $_POST["a_string_of_unspecified_length"]