I am new to regular expressions, and I am just tired by really studying all of the regex charatcer and all. I need to know what is the purpose of greater than symbol in regex for eg:
preg_match('/(?<=<).*?(?=>)/', 'sadfas<email@email.com>', $email);
Please tell me the use of greater than symbo and less than symbol in regex.
The greater than symbol simply matches the literal > at the end of your target string.
The less than symbol is not so simple. First let's review the lookaround syntax:
The pattern (?<={pattern}) is a positive lookbehind assertion, it tests whether the currently matched string is preceded by a string matching {pattern}.
The pattern (?={pattern}) is a positive lookahead assertion, it tests whether the currently matched string is followed by a string matching {pattern}.
So breaking down your expression
(?<=<) assert that the currently matched string is preceded by a literal <.*? match anything zero or more times, lazily(?=>) assert than the currently matched string is followed by a literal >Putting it all together the pattern will extract email@email.com from the input string you have given it.
Your regex is using lookarounds to capture email address between < and > characters. In your example input it captures email@email.com.
Explanation:
(?<=<) Positive Lookbehind - Assert that the regex below can be matched
< matches the character < literally
.*? matches any character (except newline)
Quantifier: Between zero and unlimited times, as few times as possible,
expanding as needed [lazy]
(?=>) Positive Lookahead - Assert that the regex below can be matched
> matches the character > literally
