In regular expressions groups can be used. Different types of groups have different notations.
These notations sometimes only differ as little as one character. This can be confusing.
To make it easier to distinguish between the different group types, they are all listen here.
The following groups are available in Regular expressions:
(…)
Capturing group and(?<…>…)
named capturing group(?:…)
Non-capturing group(?!…)
Negative Lookahead(?=…)
Positive Lookahead(?<!…)
Negative Lookbehind(?<=…)
Positive Lookbehind
Lookahead and lookbehind are also non-capturing groups. Together they are known as "lookarounds".