Regular Expressions 101

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/
(?:(.*)?((?:\/\/.*|--.*|\/\*.*\*\/))(.*))
/
g
Non-capturing group
(?:(.*)?((?:\/\/.*|--.*|\/\*.*\*\/))(.*))
1st Capturing Group
(.*)?
? matches the previous token between zero and one times, as many times as possible, giving back as needed (greedy)
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
2nd Capturing Group
((?:\/\/.*|--.*|\/\*.*\*\/))
Non-capturing group
(?:\/\/.*|--.*|\/\*.*\*\/)
1st Alternative
\/\/.*
\/ matches the character / with index 4710 (2F16 or 578) literally (case sensitive)
\/ matches the character / with index 4710 (2F16 or 578) literally (case sensitive)
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
2nd Alternative
--.*
--
matches the characters -- literally (case sensitive)
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
3rd Alternative
\/\*.*\*\/
\/ matches the character / with index 4710 (2F16 or 578) literally (case sensitive)
\* matches the character * with index 4210 (2A16 or 528) literally (case sensitive)
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
\* matches the character * with index 4210 (2A16 or 528) literally (case sensitive)
\/ matches the character / with index 4710 (2F16 or 578) literally (case sensitive)
3rd Capturing Group
(.*)
.
matches any character (except for line terminators)
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
Global pattern flags
g modifier: global. All matches (don't return after first match)
Your regular expression does not match the subject string.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
g

Test String