Regular Expressions 101

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"
>(?=([^\"\']*(\"|\')[^\"\']*(\"|\'))*(?![^\"\']*(\"|\')))
"
gm
> matches the character > with index 6210 (3E16 or 768) literally (case sensitive)
Positive Lookahead
(?=([^\"\']*(\"|\')[^\"\']*(\"|\'))*(?![^\"\']*(\"|\')))
Assert that the Regex below matches
1st Capturing Group
([^\"\']*(\"|\')[^\"\']*(\"|\'))*
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
A repeated capturing group will only capture the last iteration. Put a capturing group around the repeated group to capture all iterations or use a non-capturing group instead if you're not interested in the data
Match a single character not present in the list below
[^\"\']
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
\" matches the character " with index 3410 (2216 or 428) literally (case sensitive)
\' matches the character ' with index 3910 (2716 or 478) literally (case sensitive)
2nd Capturing Group
(\"|\')
1st Alternative
\"
\" matches the character " with index 3410 (2216 or 428) literally (case sensitive)
2nd Alternative
\'
\' matches the character ' with index 3910 (2716 or 478) literally (case sensitive)
Match a single character not present in the list below
[^\"\']
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
\" matches the character " with index 3410 (2216 or 428) literally (case sensitive)
\' matches the character ' with index 3910 (2716 or 478) literally (case sensitive)
3rd Capturing Group
(\"|\')
1st Alternative
\"
\" matches the character " with index 3410 (2216 or 428) literally (case sensitive)
2nd Alternative
\'
\' matches the character ' with index 3910 (2716 or 478) literally (case sensitive)
Negative Lookahead
(?![^\"\']*(\"|\'))
Assert that the Regex below does not match
Match a single character not present in the list below
[^\"\']
* matches the previous token between zero and unlimited times, as many times as possible, giving back as needed (greedy)
\" matches the character " with index 3410 (2216 or 428) literally (case sensitive)
\' matches the character ' with index 3910 (2716 or 478) literally (case sensitive)
4th Capturing Group
(\"|\')
1st Alternative
\"
\" matches the character " with index 3410 (2216 or 428) literally (case sensitive)
2nd Alternative
\'
\' matches the character ' with index 3910 (2716 or 478) literally (case sensitive)
Global pattern flags
g modifier: global. All matches (don't return after first match)
m modifier: multi line. Causes ^ and $ to match the begin/end of each line (not only begin/end of string)
Your regular expression does not match the subject string.

Regular Expression
No Match

r"
"
gm

Test String