Regular Expressions 101

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/
(^.*\?)([^\?].*(?=<))(<\/br>)
/
gm
1st Capturing Group
(^.*\?)
^ asserts position at start of a line
.
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 6310 (3F16 or 778) literally (case sensitive)
2nd Capturing Group
([^\?].*(?=<))
Match a single character not present in the list below
[^\?]
\? matches the character ? with index 6310 (3F16 or 778) 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)
Positive Lookahead
(?=<)
Assert that the Regex below matches
< matches the character < with index 6010 (3C16 or 748) literally (case sensitive)
3rd Capturing Group
(<\/br>)
< matches the character < with index 6010 (3C16 or 748) literally (case sensitive)
\/ matches the character / with index 4710 (2F16 or 578) literally (case sensitive)
br>
matches the characters br> 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.Try launching the debugger to find out why.

Regular Expression
No Match

/
/
gm

Test String

Substitution

Processing...