检查字符串中特定单词后是否存在括号[包含字母数字字符]的正则表达式

Question

I need regular expression to check whether square bracket [] containing alphpnumeric characters exists in string. Bracket should be after Subject: word.

sometext..Subject: Auto Reply Re: Some information, anything [0000] continue with anything

I have regular expression as preg_match('#\\[(.*?)\\]#', $text, $match); print $match[1]; preg_match('#\\[(.*?)\\]#', $text, $match); print $match[1];

It should return 0000 as output

Answer 1

This will find "subject" and capture the following contents of a square bracket.

$text ="sometext [1111] ..Subject: Auto Reply Re: Some information, anything [0000] continue with anything";

preg_match('#Subject.*?\[(.*?)\]#', $text, $match);
print $match[1]; //0000