RegEx for underlining text - regex

How can I match one line of text with a regex and follow it up with a line of dashes exactly as many as characters in the initial match to achieve text-only underlining. I intend to use this with the search and replace function (likely in the scope of a macro) inside an editor. Probably, but not necessarily, Visual Studio Code.
This is a heading
should turn into
This is a heading
-----------------
I believe I have read an example for that years ago but can't find it; neither do I seem to be able to formulate a search query to get anything useful out of Google (including variations of the question's title). If you are I'd be interested in that, too.

The best I can come up with is this:
^(.)(?=(.*\n?))|.
Substitution
$1$2-
syntax
note
^(.)
match the first character of a line, capture it in group 1
(?=(.*\n?))
then look ahead for the rest of this line and capture it in group 2, including a line break if there's any
|.
or a normal character
But the text must has a line break after it, or the underline only stays on the same line.
Not sure if it is any useful but here are the test cases.

Related

Regex NotePad++ or batch script to find and replace double bracketed text with CR LF -- would prefer NP++

I managed to do most of my conversion in VBA Macro (Word > txt) but some changes were made also that I could not forego or get around. Unfortunately, I had not been in the habit of using styles and precise formatting in my docs... (Which is why a PanDoc conversion did not "pan" out well, if you'll excuse the pun.)
In my docs, I was using bold text/lines for in-text titles (not Heading 2 alas) but as I was converting mid-sentence one or two-word bold phrases into phrases to go between double square brackets, the makeshift titles/headings were also changed to [[some title]] format in the process.
With Find and Replace (a batch script that goes through all files in a folder would also do), I would like to search for each and any number of instances of CRLF [[some title CRLF]]CRLF and replace the brackets with ** (to make the title bold), or perhaps ## to make the headings I was missing back in MS Word (I would of course need the line breaks as well).
For better understanding, please see attached picture here:
I am fairly sure that all instances are similarly syntaxed. If not, I may be able to tailor your regex code to differing instances later on.
As you can see, I was trying to do it in two steps but that's not good, because the second step (which I couldn't even get right) would propably have altered other texts I need intact (there must be sentences that start with double brackets after CRLF).
I would need the two steps in one so that only the targeted double bracketed text would be changed to bold or Heading 2.
Basically what I could not do is: find the proper regex solution for matching double CRLF-ed and square-bracketed text for any number of words than may occupy more than one line and starts with a capital letter. I would need an empty line above and below the title as indicated in the image (the VBA macro somehow made two instances of CRLF and carried the brackets to a new line, which I do not like, either).
EDIT.
In the meantime I managed to cook something up but now I couldn't insert the CRLF in front of the match string. At this point this is not enough as other instances are also changed, even lowercase in-line items, for some reason...
Regex:
\[\[([A-Z][\S\s]+?)\]\]
Substitution:
## $1\r\n
https://regex101.com/r/mH6B9N/1
Since then, I made improvements towards what I wanted (I had to test in NotePad++ and not Regex101, for different results), but now in multiple documents I have found match across spill-over lines, as described in here:
Single line regex search in Notepad++
Is it possible that I cannot do what I want? The problem is having non-title text strings having line-break, double brackets and capitalized letters.
What it looks like in other documents:
See here.
I circled around with red in image for clarification. See also:
https://regex101.com/r/8XsIGx/1
Is it possible to match a certain word like "címnél" and not execute on that match if that word is present in a line?
Thanks very much in advance,
F.
You can use
(?s)\R\K\[\[((?:(?!\[\[|]]).)*)\R*]](?=\R)
Replace with ## $1. See the regex demo.
Details:
(?s) - equivalent of the . matches newline option
\R - a line break sequence
\K - omit the text matched so far (the newlines)
\[\[ - a [[ text
((?:(?!\[\[|]]).)*) - Group 1: any char, as many as possible occurrences, that does not start a [[ or ]] char sequence
\R* - zero or more line breaks
]] - a ]] text
(?=\R) - immediately to the right, there must be a line break.

Regex: Replace double double quotes (solved), but only in lines that contain a special string (subcondition unsolved)

1. Summary of the problem
I have a csv file where I want to replace normal quotes in text with typographic ones.
It was hard (because HTML is also included), but I have meanwhile created a good regex expression that does just the right thing: in three "capturing groups" I find the left and right quotation marks and the text inside. Replacing then is a piece of cake.
2. Regex engine
I can use the regex engine of Notepad++ (boost) or PCRE2 comaptible, for developping and testing purposes I have used https://regex101.com.
3. What I'm having a hard time with and just can't get right, where I need your help is here:
I want to add a sub condition, in order to find the text in quotes only in certain lines, want to identify these lines by the language, e.g. ENGLISH or FRENCH (see also example in the screenshot).
Screenshot of a sample
The string indicating the language is always in the same line before the text to be found, BUT only the text in quotes (main condition) should be marked after matching the sub condition, so that I will be able to replace them.
It is about a few thousand records in the csv file, in the worst case I could also replace it manually. But I'm pretty sure that this should also work via regex.
4. What I have tried
Different approaches with look arounds and non-capturing groups didn't lead me to the desired result - possibly because I didn't really understand how they work.
An example can be found here: https://regex101.com/r/ketwwm/1
The example can be found here, it only contains the regex expression to match and mark the (three) groups WITHOUT the searched subcondition:
("")([^<>]*?)("")(?=(?:[^>]*?(?:<|$)))
Hopefully anyone in the community could help? (Hopefully I have not missed anything, it's my first post here )
5. Update 03/18/2022: Almost resolved with two slightly different approaches (thank you all!) What is still unsolved ..
Solution of #Thefourthbird (see answer 1)
^(?!.?"ENGLISH")[^"]".*(SKIP)(F)|("")([^<>]?)("")(?=(?:[^>]?(?:<|$)))
Nearly perfect, just missing matches in an HTML section. HTML sections in the csv file are always enclosed by double quotes and may have line feeds (LF). https://regex101.com/r/x5shnx/1
Solution of #Wiktor Stribiżew (see in comments below)
^.?"ENGLISH".?\K("")([^<>]?)("")(?=(?:[^>]?(?:<|$)))
The same with matches in HTML sections, see above. Plus: Doesn't match text in double double quotes if more than one such entry occurs within a text. https://regex101.com/r/I4NTdb/1
Screenshot (only to illustrate)
If you want to match multiple occasions, you can use SKIP matching all lines that do not start with FRENCH:
^"(?!FRENCH")[^"]*".*(*SKIP)(*F)|("")([^<>]*?)("")(?=(?:[^>]*?(?:<|$)))
The pattern matches:
^ Start of string
" Match literally
(?!FRENCH") Negative lookhead, assert not FRENCH" directly to the right
[^"]*" Match any char except " and match "
.*(*SKIP)(*F) Match the rest of the line and skip it
| Or
("")([^<>]*?)("")(?=(?:[^>]*?(?:<|$))) Your current pattern
Regex demo

Backreference Bug in Notepad++ Non-Consecutive Line Duplication Finder Regex

There seems to be a bug in the Notepad++ find/replace behaviour when using a backreference to find duplicate lines that may not necessarily be consecutive. I'm wondering if anyone knows what the issue could be with the regex or if they know why the regex engine might be bugging out?
Details
I wanted to use a regex to find duplicate lines in Notepad++. The duplicates needn't necessarily be contiguous i.e. on consecutive lines, there can be lines in between. I started with this post:
https://medium.com/#heitorhherzog/compare-sort-and-delete-duplicate-lines-in-notepad-2d1938ed7009
But realised that the regex mentioned there only checks for contiguous duplicates. So I wrote my own regex:
^(.+)$(?:(?:\s|.)+)^(\1)$
The above basically captures something on a whole line, then matches a load of stuff in between, then captures the same thing about on a line.
What's wrong
The regex works, but only sometimes. I can't figure out the pattern. I've whittled it down to this so far. If I do a "Replace All" on the replacement pattern \1\2 then the "replace all" leaves me with just line 3, which is "elative backreferences32". This is wrong:
dasfdasfdsfasdfasdfadsfasdf
elative backreferenceswe
elative backreferences32
elative backreferencesd
elative backreferencdesdfdasdfsdafsd
asfasdfasdfasdfasdfasfdsaasdfas
asdfasdfafds asdfasfdsafasd asdfdasfsd
elative backreferencessfhdfg
x
y
x
But if I delete any line from that file, then only the consecutive lines x then y then x are replaced by a single line xx as I'd expect.
Notes
I'd like to keep this question focused mostly on why the regex is
bugging out. Suggestions about alternative ways to find duplicate
lines are of course good but the main reason I'm asking this is to
figure out what's going on with the regex and Notepad++.
I don't really need the replace part of this, just the find, I was just using the replace to try to figure out what groups were being captured in an attempt to debug this
The find behaviour is also buggy. I noticed this first actually. It first finds the match I'm actually looking for, and then if I click "Find Next" again, it highlights all the text.
Hypotheses
There is a bug in Notepad++ v7.8.4 64 bit. I just updated today so maybe they haven't caught it yet.
Does the in-between part of the match, (?:(?:\s|.)+), maybe cycle
around past the end of file character and loop right back to the
original match? If so, I'd say that's still a bug, because AFAIK a
regex should only consume each character once.
I thought there might be a limit to the number of characters in the file, but I disproved this hypothesis by playing around with the file, adding characters here and there. Two files with the same number of lines and the same number of characters can behave differently: one with buggy behaviour, one without.
Screenshots
Before
After Without Matches Newline (The intended configuration)
After With Matches Newline (for Experimentation)
(?:\s|.) should be avoid as it causes unexpected behaviour, I suggest using [\s\S] instead:
Find what: ^(.+)$[\s\S]+?^(\1)$
Replace with: $1$2

How to search and replace from the last match of a until b?

I have a latex file in which I want to get rid of the last \\ before a \end{quoting}.
The section of the file I'm working on looks similar to this:
\myverse{some text \\
some more text \\}%
%
\myverse{again some text \\
this is my last line \\}%
\footnote{possibly some footnotes here}%
%
\end{quoting}
over several hundred lines, covering maybe 50 quoting environments.
I tried with :%s/\\\\}%\(\_.\{-}\)\\end{quoting}/}%\1\\end{quoting}/gc but unfortunately the non-greedy quantifier \{-} is still too greedy.
It catches starting from the second line of my example until the end of the quoting environment, I guess the greedy quantifier would catch up to the last \end{quoting} in the file. Is there any possibility of doing this with search and replace, or should I write a macro for this?
EDIT: my expected output would look something like this:
this is my last line }%
\footnote{possibly some footnotes here}%
%
\end{quoting}
(I should add that I've by now solved the task by writing a small macro, still I'm curious if it could also be done by search and replace.)
I think you're trying to match from the last occurrence of \\}% prior to end{quoting}, up to the end{quoting}, in which case you don't really want any character (\_.), you want "any character that isn't \\}%" (yes I know that's not a single character, but that's basically it).
So, simply (ha!) change your pattern to use \%(\%(\\\\}%\)\#!\_.\)\{-} instead of \_.\{-}; this means that the pattern cannot contain multiple \\}% sequences, thus achieving your aims (as far as I can determine them).
This uses a negative zero-width look-ahead pattern \#! to ensure that the next match for any character, is limited to not match the specific text we want to avoid (but other than that, anything else still matches). See :help /zero-width for more of these.
I.e. your final command would be:
:%s/\\\\}%\(\%(\%(\\\\}%\)\#!\_.\)\{-}\)\\end{quoting}/}%\1\\end{quoting}/g
(I note your "expected" output does not contain the first few lines for some reason, were they just omitted or was the command supposed to remove them?)
You’re on the right track using the non-greedy multi. The Vim help files
state that,
"{-}" is the same as "*" but uses the shortest match first algorithm.
However, the very next line warns of the issue that you have encountered.
BUT: A match that starts earlier is preferred over a shorter match: "a{-}b" matches "aaab" in "xaaab".
To the best of my knowledge, your best solution would be to use the macro.

Regex: remove lines not starting with a digit

I have been fighting this problem with the help of a RegEx cheat sheet, trying to figure out how to do this, but I give up... I have this lengthy file open in Notepad++ and would like to remove all lines that do not start with a digit (0..9). I would use the Find/Replace functionality of N++. I am only mentioning this as I am not sure what Regex implementation is N++ using... Thank you
Example. From the following text:
1hello
foo
2world
bar
3!
I would like to extract
1hello
2world
3!
not:
1hello
2world
3!
by doing a find/replace on a regular expression.
You can clear up those line with ^[^0-9].* but it will leave blank lines.
Notepad++ use scintilla, and also using its regex engine to match those.
\r and \n are never matched because in
Scintilla, regular expression searches
are made line per line (stripped of
end-of-line chars).
http://www.scintilla.org/SciTERegEx.html
To clear up those blank lines, only way is choose extended mode, and replace \n\n to \n, If you are in windows mode change \r\n\r\n to \r\n
[^0-9] is a regular expression that matches pretty much anything, except digits. If you say ^[^0-9] you "anchor" it to the start of the line, in most regular expression systems. If you want to include the rest of the line, use ^[^0-9].+.
^[^\d].* marks a whole line whose first character is not a digit. Check if there are really no whitespaces in front of the digits. Otherwise you'd have to use a different expression.
UPDATE:
You will have to do ot in two steps. First empty the lines that do not start with a digit. Then remove the empty lines in extended mode.
One could also use the technique of bookmarking in Notepad++. I started benefiting from this feature (long time present but only more recently made somewhat more visible in the UI) not very long ago.
Simply bring up the find dialogue, type regex for lines not starting with digit ^\D.*$ and select Mark All. This will place blue circles, like marbles, in the left gutter - these are line bookmarks. Then just select from main menu Search -> Bookmark -> Remove bookmarked lines.
Bookmarks are cool, you could extract these lines by simply selecting to copy bookmarked lines, opening new document and pasting lines there. I sometimes use this technique when reviewing log files.
I'm not sure what you are asking. but the reg exp for finding the lines with a digit at the beginning would be
^\d.*
you can remove all the lines that match the above or alternatly keep all the lines that match this expression:
^[^\d].*