string - Which would be better non-greedy regex or negated character class?

Question

I need to match @anything_here@ from a string @anything_here@dhhhd@shdjhjs@. So I'd used following regex.

^@.*?@

or

^@[^@]*@

Both way it's work but I would like to know which one would be a better solution. Regex with non-greedy repetition or regex with negated character class?

Answer 1

It is clear the ^@[^@]*@ option is much better.

The negated character class is quantified greedily which means the regex engine grabs 0 or more chars other than @ right away, as many as possible. See this regex demo and matching:

When you use a lazy dot matching pattern, the engine matches @, then tries to match the trailing @ (skipping the .*?). It does not find the @ at Index 1, so the .*? matches the a char. This .*? pattern expands as many times as there are chars other than @ up to the first @.

See the lazy dot matching based pattern demo here and here is the matching steps: