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Exact search of a string that has parenthesis using regex

I am new to regexes.
I have the following string : \n(941)\n364\nShackle\n(941)\nRivet\n105\nTop
Out of this string, I want to extract Rivet and I already have (941) as a string in a variable.
My thought process was like this:
Find all the (941)s
filter the results by checking if the string after (941) is followed by \n, followed by a word, and ending with \n
I made a regex for the 2nd part: \n[\w\s\'\d\-\/\.]+$\n.
The problem I am facing is that because of the parenthesis in (941) the regex is taking 941 as a group. In the 3rd step the regex may be wrong, which I can fix later, but 1st I needed help in finding the 2nd (941) so then I can apply the 3rd step on that.
PS.
I know I can use python string methods like find and then loop over the searches, but I wanted to see if this can be done directly using regex only.
I have tried the following regex: (?:...), (941){1} and the make regex literal character \ like this \(941\) with no useful results. Maybe I am using them wrong.
Just wanted to know if it is possible to be done using regex. Though it might be useful for others too or a good share for future viewers.
Thanks!

Assuming:
You want to avoid matching only digits;
Want to match a substring made of word-characters (thus including possible digits);
Try to escape the variable and use it in the regular expression through f-string:
import re
s = '\n(941)\n364\nShackle\n(941)\nRivet\n105\nTop'
var1 = '(941)'
var2 = re.escape(var1)
m = re.findall(fr'{var2}\n(?!\d+\n)(\w+)', s)[0]
print(m)
Prints:
Rivet

If you have text in a variable that should be matched exactly, use re.escape() to escape it when substituting into the regexp.
s = '\n(941)\n364\nShackle\n(941)\nRivet\n105\nTop'
num = '(941)'
re.findall(rf'(?<=\n{re.escape(num)}\n)[\w\s\'\d\-\/\.]+(?=\n)', s)
This puts (941)\n in a lookbehind, so it's not included in the match. This avoids a problem with the \n at the end of one match overlapping with the \n at the beginning of the next.

Regex: Stop when it finds the first ocurrence of a character [duplicate]

I am looking for a pattern that matches everything until the first occurrence of a specific character, say a ";" - a semicolon.
I wrote this:
/^(.*);/
But it actually matches everything (including the semicolon) until the last occurrence of a semicolon.

You need
/^[^;]*/
The [^;] is a character class, it matches everything but a semicolon.
^ (start of line anchor) is added to the beginning of the regex so only the first match on each line is captured. This may or may not be required, depending on whether possible subsequent matches are desired.
To cite the perlre manpage:
You can specify a character class, by enclosing a list of characters in [] , which will match any character from the list. If the first character after the "[" is "^", the class matches any character not in the list.
This should work in most regex dialects.

Would;
/^(.*?);/
work?
The ? is a lazy operator, so the regex grabs as little as possible before matching the ;.

/^[^;]*/
The [^;] says match anything except a semicolon. The square brackets are a set matching operator, it's essentially, match any character in this set of characters, the ^ at the start makes it an inverse match, so match anything not in this set.

None of the proposed answers did work for me. (e.g. in notepad++)
But
^.*?(?=\;)
did.

Try /[^;]*/
Google regex character classes for details.

sample text:
"this is a test sentence; to prove this regex; that is g;iven below"
If for example we have the sample text above, the regex /(.*?\;)/ will give you everything until the first occurence of semicolon (;), including the semicolon: "this is a test sentence;"

Try /[^;]*/
That's a negating character class.

This was very helpful for me as I was trying to figure out how to match all the characters in an xml tag including attributes. I was running into the "matches everything to the end" problem with:
/<simpleChoice.*>/
but was able to resolve the issue with:
/<simpleChoice[^>]*>/
after reading this post. Thanks all.

this is not a regex solution, but something simple enough for your problem description. Just split your string and get the first item from your array.
$str = "match everything until first ; blah ; blah end ";
$s = explode(";",$str,2);
print $s[0];
output
$ php test.php
match everything until first

This will match up to the first occurrence only in each string and will ignore subsequent occurrences.
/^([^;]*);*/

"/^([^\/]*)\/$/" worked for me, to get only top "folders" from an array like:
a/ <- this
a/b/
c/ <- this
c/d/
/d/e/
f/ <- this

Really kinda sad that no one has given you the correct answer....
In regex, ? makes it non greedy. By default regex will match as much as it can (greedy)
Simply add a ? and it will be non-greedy and match as little as possible!
Good luck, hope that helps.

This works for getting the content from the beginning of a line till the first word,
/^.*?([^\s]+)/gm

I faced a similar problem including all the characters until the first comma after the word entity_id. The solution that worked was this in Bigquery:
SELECT regexp_extract(line_items,r'entity_id*[^,]*')

Regex to replace filepaths in a string when there's more than one in Python

I'm having trouble finding a way to match multiple filepaths in a string while maintaining the rest of the string.
EDIT: forgot to add that the filepath might contain a dot, so edited "username" to user.name"
# filepath always starts with "file:///" and ends with file extension
text = """this is an example text extracted from file:///c:/users/user.name/download/temp/anecdote.pdf
1 of 4 page and I also continue with more text from
another path file:///c:/windows/system32/now with space in name/file (1232).html running out of text to write."""
I've found many answers that work, but fails when theres more than one filepath, also replacing the other characters in between.
import re
fp_pattern = r"file:\/\/\/(\w|\W){1,255}\.[\w]{3,4}"
print(re.sub(fp_pattern, "*IGOTREPLACED*", text, flags=re.MULTILINE))
>>>"this is an example text extracted from *IGOTREPLACED* running out of text to write."
I've also tried using a "stop when after finding a whitespace after the pattern" but I couldn't get one to work:
fp_pattern = r"file:\/\/\/(\w|\W){1,255}\.[\w]{3,4} ([^\s]+)"
>>> 0 matches

Note that {1,255} is a greedy quantifier, and will match as many chars as possible, you need to add ? after it.
However, just using a lazy {1,255}? quantifier won't solve the problem. You need to define where the match should end. It seems you only want to match these URLs when the extension is immediately followed with whitespace or end of string.
Hence, use
fp_pattern = r"file:///.{1,255}?\.\w{3,4}(?!\S)"
See the regex demo
The (?!\S) negative lookahead will fail any match if, immediately to the right of the current location, there is a non-whitespace char. .{1,255}? will match any 1 to 255 chars, as few as possible.
Use in Python as
re.sub(fp_pattern, "*IGOTREPLACED*", text, flags=re.S)
The re.MULTILINE (re.M) flag only redefines ^ and $ anchor behavior making them match start/end of lines rather than the whole string. The re.S flag allows . to match any chars, including line break chars.
Please never use (\w|\W){1,255}?, use .{1,255}? with re.S flag to match any char, else, performance will decrease.

You can try re.findall to find out how many time regex matches in string. Hope this helps.
import re
len(re.findall(pattern, string_to_search))

Preserve key:value values in text while regex replacing non-word characters in keys (Notepad++)

Trying without luck in Notepad++ to replace any non-word characters \W with underscore _ from a block of multi-line text, with exception to (and right of) a colon : (which doesn't occur on every line- something of space-delineated hierarchy, terminating in a key-value pair). A python solution could be of use as well, as I'm trying to do other things with it once reformatted. Example:
This 100% isn't what I want
Yet, it's-what-I've got currently: D#rnit :(
This_100_is_what_I_d_like: See?
Indentation_isn_t_necessary
_to_maintain_but_would_be_nice: :)<-preserved!
I_m_Mr_Conformist_over_here: |Whereas, I'm like whatever's clever.|
If_you_can_help: Thanks 100.1%!

I admit that I'm answering an off-topic question I just liked the problem. Hold CTRL+H, enable Regular Expressions in N++ then search for:
(:[^\r\n]*|^\s+)|\W(?<![\r\n])
And replace with:
(?1\1:_)
Regex has two main parts. First side of outer alternation which matches leading spaces of a line (indentation) or every thing after first occurrence of a colon, and second side which matches a non-word character except a carriage return \r or newline \n character (in negative lookbehind) to preserve linebreaks. Replacement string is a conditional block which says if first capturing group is matched replace it with itself and if not replace it with a _.

Seeing a better description of what you're trying to do, I don't think you'll be able to do it from inside notepad++ using a single regular expression. However, you could write a python script that scrolls through your document, one line at time, and sanitizes anything to the left of a colon (if one exists)
Here's a quick and dirty example (untested). This assumes doc is an open file pointer to the file you want to sanitize
import re
sanitized_lines = []
for line in doc:
line_match = re.match(r"^(\s*)([^:\n]*)(.*)", line)
indentation = line_match.group(1)
left_of_colon = line_match.group(2)
remainder = line_match.group(3)
left_of_colon = re.sub(r"\W", "_", left_of_colon)
sanitized_lines.append("".join((indentation, left_of_colon, remainder)))
sanitized_doc = "".join(sanitized_lines)
print(sanitized_doc)

You may try this python script,
ss="""This 100% isn't what I want
Yet, it's-what-I've got currently: D#rnit :(
If you can help: Thanks 100.1%!"""
import re
splitcapture=re.compile(r'(?m)^([^:\n]+)(:[^\n]*|)$')
subregx=re.compile(r'\W+')
print(splitcapture.sub(lambda m: subregx.sub('_', m.group(1))+m.group(2), ss))
in which first I tried to match each line and capture 2 parts separately(the one part not containing ':'character is capured to group 1, and the other possible part started with ':' and goes on to the end of the line is captured to group 2), and then implemented replacing process only on group 1 captured string and finally joined 2 parts, replaced group 1 + group 2
And output is
This_100_isn_t_what_I_want_
_Yet_it_s_what_I_ve_got_currently: D#rnit :(
If_you_can_help: Thanks 100.1%!

Regex replace everything except match

I would like to keep just words that start with '#' and continue with letters or dots. Basically I have done opposite that I can match such a words but don't know how to match everything besides this match. So basically just keep those that starts with '#'. So far I have this patter:
(#[a-zA-Z0-9.]+\b)
I tried to use '?!' but it doesn't work. Thanks!

From the comments, the following regex is ok
(?:^|\s)[^#]*
exact contrary would be
(?:^|[^#A-Za-z0-9.]|#(?![A-Za-z0-9.]+\b))[^#]*

Try with this Regex Expression:
(#+[a-zA-Z0-9.]+[a-zA-Z0-9]+)
I tested it on-line and it does what you are looking for ( match every words that starts with # and it can continue with dots, es: #hello.sir match | #hello.sir.do match and so on.. )