Regular Expressions 101

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/
(?| (")((?:\\"|[^"])+)\1 | (')((?:\\'|[^'])+)\1 )
/
xg
Branch Reset Group
(?| (")((?:\\"|[^"])+)\1 | (')((?:\\'|[^'])+)\1 )
Subpatterns declared within each alternative of this construct will start over from the same index.
1st Alternative
(")((?:\\"|[^"])+)\1
1st Capturing Group
(")
" matches the character " with index 3410 (2216 or 428) literally (case sensitive)
2nd Capturing Group
((?:\\"|[^"])+)
Non-capturing group
(?:\\"|[^"])+
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
1st Alternative
\\"
\\ matches the character \ with index 9210 (5C16 or 1348) literally (case sensitive)
" matches the character " with index 3410 (2216 or 428) literally (case sensitive)
2nd Alternative
[^"]
Match a single character not present in the list below
[^"]
" matches the character " with index 3410 (2216 or 428) literally (case sensitive)
\1 matches the same text as most recently matched by the 1st capturing group
2nd Alternative
(')((?:\\'|[^'])+)\1
1st Capturing Group
(')
' matches the character ' with index 3910 (2716 or 478) literally (case sensitive)
2nd Capturing Group
((?:\\'|[^'])+)
Non-capturing group
(?:\\'|[^'])+
+ matches the previous token between one and unlimited times, as many times as possible, giving back as needed (greedy)
1st Alternative
\\'
\\ matches the character \ with index 9210 (5C16 or 1348) literally (case sensitive)
' matches the character ' with index 3910 (2716 or 478) literally (case sensitive)
2nd Alternative
[^']
Match a single character not present in the list below
[^']
' matches the character ' with index 3910 (2716 or 478) literally (case sensitive)
\1 matches the same text as most recently matched by the 1st capturing group
Global pattern flags
x modifier: extended. Spaces and text after a # in the pattern are ignored
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

/
/
xg

Test String