A little late to this thread - just to build on ryanp's answer.
Assuming you have the string aaabbbccc
Regular Expression
(a)+(b)+(c)+
This would give you the following 3 groups that matched:
['a', 'b', 'c']
Regular Expression with non-capturing parenthesis
Use the ?: in the first group
(?:a)+(b)+(c)+
and you would get the following groups that matched:
['b', 'c']
Hence why it is called "non-capturing parenthesis"
Example use case:
Sometime you use parenthesis for other things. For example to set the bounds of the | or operator:
"New (York|Jersey)"
In this case, you are only using the parenthesis for the or | switch, and you don't really want to capture this data. Use the non-capturing parenthesis to indicate that:
"New (?:York|Jersey)"
