Regular Expressions 101

Pro

<c>the literal text <c> (case sensitive)

Group 1(<.>)?

?repeats the group contents below at most once:

<the literal < (60₁₀ / 74₈ / 3C₁₆)

.any character (except for line terminators)

>the literal > (62₁₀ / 76₈ / 3E₁₆)

Condition(?(1).+?</c>)

Uses the first branch if group 1 matched

If the condition is true, match this branch:.+?</c>

.+?any character (except for line terminators), repeated at least once

</c>the literal text </c> (case sensitive)

.+?any character (except for line terminators), repeated at least once

Group 2(</c>)?

?repeats the group contents below at most once:

</c>the literal text </c> (case sensitive)

(?2)++calls group 2 as a subroutine, repeated at least once

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

Detailed match information will be displayed here automatically.

25 tokens

<c>(<.>)?(?(1).+?</c>).+?(</c>)?(?2)++

New

<c><c><c>bbbb</c></c></c>
ffff
<c><p><c><c>bbbb</c></c></p></c> 
aaaa
<c>bbbb</c>
dddd
<p><c>eeee</c>оставить подстроку</p>
ffff

<c><c><c>bbbb</c></c></c>
ffff
<c><p><c><c>bbbb</c></c></p></c> 
aaaa
<c>bbbb</c>
dddd
<p><c>eeee</c>оставить подстроку</p>
ffff