Regular Expressions 101

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/
(\S+), (\S+)(.*(?!,)).*?\n
/
g
1st Capturing Group
(\S+)
\S
matches any non-whitespace character (equivalent to [^\r\n\t\f\v ])
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
,
matches the characters , literally (case sensitive)
2nd Capturing Group
(\S+)
\S
matches any non-whitespace character (equivalent to [^\r\n\t\f\v ])
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
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)
Negative Lookahead
(?!,)
Assert that the Regex below does not match
, matches the character , with index 4410 (2C16 or 548) literally (case sensitive)
.
matches any character (except for line terminators)
*? matches the previous token between zero and unlimited times, as few times as possible, expanding as needed (lazy)
\n matches a line-feed (newline) character (ASCII 10)
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