i am trying to do a multiple match within a lookbehind and a look forward
Let's say i have the following string:
$ Hi, this is an example #
Regex: (?<=$).+a.+(?=#)
I am expecting it to return both 'a' within those boundaries, is there a way to do it with only one regex?
Engine: Python
If you can use quantifiers in the lookbehind, use
(?<=\$[^$#]*?)a(?=[^#]*#)
See proof.
Explanation
--------------------------------------------------------------------------------
(?<= look behind to see if there is:
--------------------------------------------------------------------------------
\$ '$'
--------------------------------------------------------------------------------
[^$#]*? any character except: '$' and '#' (0 or more
times (matching the least amount possible))
--------------------------------------------------------------------------------
) end of look-behind
--------------------------------------------------------------------------------
a 'a'
--------------------------------------------------------------------------------
(?= look ahead to see if there is:
--------------------------------------------------------------------------------
[^#]* any character except: '#' (0 or more
times (matching the most amount
possible))
--------------------------------------------------------------------------------
# '#'
--------------------------------------------------------------------------------
) end of look-ahead
PCRE pattern:
(?:\G(?<!^)|\$)[^$]*?\Ka(?=[^#]*#)
See another proof
Explanation
--------------------------------------------------------------------------------
(?: group, but do not capture:
--------------------------------------------------------------------------------
\G where the last m//g left off
--------------------------------------------------------------------------------
(?<! look behind to see if there is not:
--------------------------------------------------------------------------------
^ the beginning of the string
--------------------------------------------------------------------------------
) end of look-behind
--------------------------------------------------------------------------------
| OR
--------------------------------------------------------------------------------
\$ '$'
--------------------------------------------------------------------------------
) end of grouping
--------------------------------------------------------------------------------
[^$#]*? any character except: '$' and '#' (0 or more times
(matching the least amount possible))
--------------------------------------------------------------------------------
\K match reset operator
--------------------------------------------------------------------------------
a 'a'
--------------------------------------------------------------------------------
(?= look ahead to see if there is:
--------------------------------------------------------------------------------
[^#]* any character except: '#' (0 or more
times (matching the most amount
possible))
--------------------------------------------------------------------------------
# '#'
--------------------------------------------------------------------------------
) end of look-ahead
Related
I have a regular expression looking for .svg files under the icons-wc/icons directory for a Webpack svgo-loader.
/icons-wc\\icons\\.*\.svg$/
I'd now like to find all .svg files outside the icons-wc/icons directory but I'm not sure how to approach it. I've tried something like this but that doesn't seem to work. It seems to be too over eager to select
/(?<!icons-wc\\icons)\\.*\.svg$/
Use
/^(?!.*(?:^|[\\\/])icons-wc[\\\/]icons[\\\/]).*\.svg$/
See regex proof.
EXPLANATION
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^ the beginning of the string
--------------------------------------------------------------------------------
(?! look ahead to see if there is not:
--------------------------------------------------------------------------------
.* any character except \n (0 or more times
(matching the most amount possible))
--------------------------------------------------------------------------------
(?: group, but do not capture:
--------------------------------------------------------------------------------
^ the beginning of the string
--------------------------------------------------------------------------------
| OR
--------------------------------------------------------------------------------
[\\\/] any character of: '\\', '\/'
--------------------------------------------------------------------------------
) end of grouping
--------------------------------------------------------------------------------
icons-wc 'icons-wc'
--------------------------------------------------------------------------------
[\\\/] any character of: '\\', '\/'
--------------------------------------------------------------------------------
icons 'icons'
--------------------------------------------------------------------------------
[\\\/] any character of: '\\', '\/'
--------------------------------------------------------------------------------
) end of look-ahead
--------------------------------------------------------------------------------
.* any character except \n (0 or more times
(matching the most amount possible))
--------------------------------------------------------------------------------
\. '.'
--------------------------------------------------------------------------------
svg 'svg'
--------------------------------------------------------------------------------
$ before an optional \n, and the end of the
string
I'm trying to extract an optional element via PCRE from the following example.
I need to pull out the xxxx-xxx-xxxx-xxxx-xxxxx if ActivityID exists.
I'm guessing I need to use lookaheads or the like but I can't quite wrap my head around it.
</Level><Task>...<Correlation ActivityID='{xxxx-xxx-xxxx-xxxx-xxxxx}'/><Execution...</Channel>
This works if the element exists, saving to taco64:
<\/level>(?<taco16>.*?)ActivityID='{(?<taco64>.*)}'(?<taco32>.*?)<Computer>
Being optional drops everything into taco32.
<\/level>(?<taco16>.*?)(ActivityID='{(?<taco64>.*)}')?(?<taco32>.*?)<Computer>
Use
<\/level>(?:(?<taco16>.*?)(ActivityID='{(?<taco64>.*)}'))?(?<taco32>.*?)<Computer>
See regex proof.
EXPLANATION
--------------------------------------------------------------------------------
< '<'
--------------------------------------------------------------------------------
\/ '/'
--------------------------------------------------------------------------------
level> 'level>'
--------------------------------------------------------------------------------
(?: group, but do not capture (optional
(matching the most amount possible)):
--------------------------------------------------------------------------------
(?<taco16> group and capture to taco16:
--------------------------------------------------------------------------------
.*? any character except \n (0 or more
times (matching the least amount
possible))
--------------------------------------------------------------------------------
) end of taco16
--------------------------------------------------------------------------------
(?<taco64> group and capture to taco64:
--------------------------------------------------------------------------------
ActivityID='{ 'ActivityID=\'{'
--------------------------------------------------------------------------------
( group and capture to \3:
--------------------------------------------------------------------------------
.* any character except \n (0 or more
times (matching the most amount
possible))
--------------------------------------------------------------------------------
) end of taco64
--------------------------------------------------------------------------------
}' '}\''
--------------------------------------------------------------------------------
) end of \2
--------------------------------------------------------------------------------
)? end of grouping
--------------------------------------------------------------------------------
(?<taco32> group and capture to taco32:
--------------------------------------------------------------------------------
.*? any character except \n (0 or more times
(matching the least amount possible))
--------------------------------------------------------------------------------
) end of taco32
--------------------------------------------------------------------------------
<Computer> '<Computer>'
I am learning regex and am working on finding the regex format to satisfy below conditions:
check the contents in between "<NoteText>" and "</NoteText>"
If there is one or more "<" symbol not followed by "!", return all the identified "<" symbols.
example:
<NoteText><![CDATA[dvsdhjkndlv <<<RED>>> <72901> </NoteText>
this should return the 3 "<" before RED and the 1 "<" before 72901
initially i tried with the below regex pattern of negative lookahead.
<(?!!)
But it returns the "<" before the "NoteText" phrase as well.
I am not sure how to limit the area of filtering in between "<NoteText>" and "</NoteText>".
trying the below way did not work as well.
(?:<NoteText>.*)(<(?!!)).*(?:<\/NoteText>)
PCRE, not pretty, but working:
(?:\G(?!\A)|<NoteText>)(?:(?!<\/?NoteText>).)*?\K<(?!!)(?=(?:(?!<\/?NoteText>).)*?<\/NoteText>)
See regex proof.
EXPLANATION
--------------------------------------------------------------------------------
(?: group, but do not capture:
--------------------------------------------------------------------------------
\G where the last m//g left off
--------------------------------------------------------------------------------
(?! look ahead to see if there is not:
--------------------------------------------------------------------------------
\A the beginning of the string
--------------------------------------------------------------------------------
) end of look-ahead
--------------------------------------------------------------------------------
| OR
--------------------------------------------------------------------------------
<NoteText> '<NoteText>'
--------------------------------------------------------------------------------
) end of grouping
--------------------------------------------------------------------------------
(?: group, but do not capture (0 or more times
(matching the least amount possible)):
--------------------------------------------------------------------------------
(?! look ahead to see if there is not:
--------------------------------------------------------------------------------
< '<'
--------------------------------------------------------------------------------
\/? '/' (optional (matching the most
amount possible))
--------------------------------------------------------------------------------
NoteText> 'NoteText>'
--------------------------------------------------------------------------------
) end of look-ahead
--------------------------------------------------------------------------------
. any character except \n
--------------------------------------------------------------------------------
)*? end of grouping
--------------------------------------------------------------------------------
\K match reset operator
--------------------------------------------------------------------------------
< '<'
--------------------------------------------------------------------------------
(?! look ahead to see if there is not:
--------------------------------------------------------------------------------
! '!'
--------------------------------------------------------------------------------
) end of look-ahead
--------------------------------------------------------------------------------
(?= look ahead to see if there is:
--------------------------------------------------------------------------------
(?: group, but do not capture (0 or more
times (matching the least amount
possible)):
--------------------------------------------------------------------------------
(?! look ahead to see if there is not:
--------------------------------------------------------------------------------
< '<'
--------------------------------------------------------------------------------
\/? '/' (optional (matching the most
amount possible))
--------------------------------------------------------------------------------
NoteText> 'NoteText>'
--------------------------------------------------------------------------------
) end of look-ahead
--------------------------------------------------------------------------------
. any character except \n
--------------------------------------------------------------------------------
)*? end of grouping
--------------------------------------------------------------------------------
< '<'
--------------------------------------------------------------------------------
\/ '/'
--------------------------------------------------------------------------------
NoteText> 'NoteText>'
--------------------------------------------------------------------------------
) end of look-ahead
This is a working method in Java 8. Remember that this works only if you don't have nested <NoteText> tags.
String myString = "<NoteText><![CDATA[dvsdhjkndlv <<<RED>>> <72901> </NoteText>";
Matcher outerMatcher = Pattern.compile("(?<=<NoteText>).*?(?=</NoteText>)").matcher(myString);
while (outerMatcher.find()) {
String content = outerMatcher.group(); // this is the content of the current NodeText tag
Matcher innerMatcher = Pattern.compile("<(?!!)").matcher(content);
int count = 0;
while (innerMatcher.find()) count++;
System.out.println(count); // this will print 4
}
The code above is thought for working also with strings of multiple occurrences of <NoteText> tags.
If you know you have only one <NoteText> tag, just replace the while with an if.
I have been using this:
~^\/student-accommodation\/(?:[^\/]+?)\/([^\/]+)\/$
to match for URLs like
/student-accommodation/manchester/ropemaker-court-manchester/
But now I need to edit this regex so it also matches for URLs like the below. All these new URLs will follow the same pattern and add a string that starts with #utm-source. Importantly they won't have another / in them.
/student-accommodation/manchester/ropemaker-court-manchester/#utm_source=afs&utm_medium=email&utm_campaign=ropemakercourt_afs_dec20
But then I don't want the regex to match for URLs like the below:
/student-accommodation/manchester/ropemaker-court-manchester/en-suite/
Can anyone help? I am a novice at regex! Thanks
Use
^\/student-accommodation\/[^\/]+\/([^\/]+)\/(?:#utm_source.*)?$
See proof
Explanation
--------------------------------------------------------------------------------
^ the beginning of the string
--------------------------------------------------------------------------------
\/ '/'
--------------------------------------------------------------------------------
student- 'student-accommodation'
accommodation
--------------------------------------------------------------------------------
\/ '/'
--------------------------------------------------------------------------------
[^\/]+ any character except: '\/' (1 or more
times (matching the most amount possible))
--------------------------------------------------------------------------------
\/ '/'
--------------------------------------------------------------------------------
( group and capture to \1:
--------------------------------------------------------------------------------
[^\/]+ any character except: '\/' (1 or more
times (matching the most amount
possible))
--------------------------------------------------------------------------------
) end of \1
--------------------------------------------------------------------------------
\/ '/'
--------------------------------------------------------------------------------
(?: group, but do not capture (optional
(matching the most amount possible)):
--------------------------------------------------------------------------------
#utm_source '#utm_source'
--------------------------------------------------------------------------------
.* any character except \n (0 or more times
(matching the most amount possible))
--------------------------------------------------------------------------------
)? end of grouping
--------------------------------------------------------------------------------
$ before an optional \n, and the end of the
string
I'd like to use mustache style for expression: {{abc}}, it's pretty easy to write /({{[a-z]+}})/.
However I cannot get it right to handle \{{abc}}, for which I'd like to skip them on match list. I tried /((?!\\)({{[a-z]+}}))/ but it doesn't work.
https://regex101.com/r/67nXA2/2
Use
(?<!\\)(?:\\\\)*\K{{[a-z]+}}
See proof
Explanation
--------------------------------------------------------------------------------
(?<! look behind to see if there is not:
--------------------------------------------------------------------------------
\\ '\'
--------------------------------------------------------------------------------
) end of look-behind
--------------------------------------------------------------------------------
(?: group, but do not capture (0 or more times
(matching the most amount possible)):
--------------------------------------------------------------------------------
\\ '\'
--------------------------------------------------------------------------------
\\ '\'
--------------------------------------------------------------------------------
)* end of grouping
--------------------------------------------------------------------------------
\K match reset operator
--------------------------------------------------------------------------------
{{ '{{'
--------------------------------------------------------------------------------
[a-z]+ any character of: 'a' to 'z' (1 or more
times (matching the most amount possible))
--------------------------------------------------------------------------------
}} '}}'