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Regex python - find match items on list that have the same digit between the second character "_" to character "."

I have the following list :
list_paths=imgs/foldeer/img_ABC_21389_1.tif.tif,
imgs/foldeer/img_ABC_15431_10.tif.tif,
imgs/foldeer/img_GHC_561321_2.tif.tif,
imgs_foldeer/img_BCL_871125_21.tif.tif,
...
I want to be able to run a for loop to match string with specific number,which is the number between the second occurance of "_" to the ".tif.tif", for example, when number is 1, the string to be matched is "imgs/foldeer/img_ABC_21389_1.tif.tif" , for number 2, the match string will be "imgs/foldeer/img_GHC_561321_2.tif.tif".
For that, I wanted to use regex expression. Based on this answer, I have tested this regex expression on Regex101:
[^\r\n_]+\.[^\r\n_]+\_([0-9])
But this doesn't match anything, and also doesn't make sure that it will take the exact number, so if number is 1, it might also select items with number 10 .
My end goal is to be able to match items in the list that have the request number between the 2nd occurrence of "_" to the first occirance of ".tif" , using regex expression, looking for help with the regex expression.
EDIT: The output should be the whole path and not only the number.

Your pattern [^\r\n_]+\.[^\r\n_]+\_([0-9]) does not match anything, because you are matching an underscore \_ (note that you don't have to escape it) after matching a dot, and that does not occur in the example data.
Then you want to match a digit, but the available digits only occur before any of the dots.
In your question, the numbers that you are referring to are after the 3rd occurrence of the _
What you could do to get the path(s) is to make the number a variable for the number you want to find:
^\S*?/(?:[^\s_/]+_){3}\d+\.tif\b[^\s/]*$
Explanation
\S*? Match optional non whitespace characters, as few as possible
/ Match literally
(?:[^\s_/]+_){3} Match 3 times (non consecutive) _
\d+ Match 1+ digits
\.tif\b[^\s/]* Match .tif followed by any char except /
$ End of string
See a regex demo and a Python demo.
Example using a list comprehension to return all paths for the given number:
import re
number = 10
pattern = rf"^\S*?/(?:[^\s_/]+_){{3}}{number}\.tif\b[^\s/]*$"
list_paths = [
"imgs/foldeer/img_ABC_21389_1.tif.tif",
"imgs/foldeer/img_ABC_15431_10.tif.tif",
"imgs/foldeer/img_GHC_561321_2.tif.tif",
"imgs_foldeer/img_BCL_871125_21.tif.tif",
"imgs_foldeer/img_BCL_871125_21.png.tif"
]
res = [lp for lp in list_paths if re.search(pattern, lp)]
print(res)
Output
['imgs/foldeer/img_ABC_15431_10.tif.tif']

I'll show you something working and equally ugly as regex which I hate:
data = ["imgs/foldeer/img_ABC_21389_1.tif.tif",
"imgs/foldeer/img_ABC_21389_1.tif.tif",
"imgs/foldeer/img_ABC_15431_10.tif.tif",
"imgs/foldeer/img_GHC_561321_2.tif.tif",
"imgs_foldeer/img_BCL_871125_21.tif.tif"]
numbers = [int(x.split("_",3)[-1].split(".")[0]) for x in data]
First split gives ".tif.tif"
extract the last element
split again by the dot this time, take the first element (thats your number as a string), cast it to int
Please keep in mind it's gonna work only for the format you provided, no flexibility at all in this solution (on the other hand regex doesn't give any neither)

without regex if allowed.
import re
s= 'imgs/foldeer/img_ABC_15431_10.tif.tif'
last =s[s.rindex('_')+1:]
print(re.findall(r'\d+', last)[0])
Gives #
10

[0-9]*(?=\.tif\.tif)
This regex expression uses a lookahead to capture the last set of numbers (what you're looking for)

Try this:
import re
s = '''imgs/foldeer/img_ABC_21389_1.tif.tif
imgs/foldeer/img_ABC_15431_10.tif.tif
imgs/foldeer/img_GHC_561321_2.tif.tif
imgs_foldeer/img_BCL_871125_21.tif.tif'''
number = 1
res1 = re.findall(f".*_{number}\.tif.*", s)
number = 21
res21 = re.findall(f".*_{number}\.tif.*", s)
print(res1)
print(res21)
Results
['imgs/foldeer/img_ABC_21389_1.tif.tif']
['imgs_foldeer/img_BCL_871125_21.tif.tif']

python regex unexpected match groups

I am trying to find all occurrences of either "_"+digit or "^"+digit, using the regex ((_\^)[1-9])
The groups I'd expect back eg for "X_2ZZZY^5" would be [('_2'), ('^5')] but instead I am getting [('_2', '_'), ('^5', '^')]
Is my regex incorrect? Or is my expectation of what gets returned incorrect?
Many thanks
** my original re used (_|\^) this was incorrect, and should have been (_\^) -- question has been amended accordingly

You have 2 groups in your regex - so you're getting 2 groups. And you need to match atleast 1 number that follows.
try this:
([_\^][1-9]+)
See it in action here

Demand at least 1 digit (1-9) following the special characters _ or ^, placed inside a single capture group:
import re
text = "X_2ZZZY^5"
pattern = r"([_\^][1-9]{1,})"
regex = re.compile(pattern)
res = re.findall(regex, text)
print(res)
Returning:
['_2', '^5']

Get last part after number regex python

I have always 2 numbers in between and I want to extract everything before 3 so Salvatore and everything after 2 Abdulla
For example I have the following:
txt = "Salvatore32Abdulla"
first = re.findall("^\D+", txt)
last = re.search(,txt)
Expected result:
first = 'Salvatore'
last = 'Abdulla'
I can get the first part, but after 2 I can't get the last part

You could also do this in a single line by slightly changing the solution suggested by #ctwheels as follows. I would suggest you to use re.findall as that gets the job done with a single blow.
import re
txt = "Salvatore32Abdulla"
Option-1
Single line extraction of the non-numeric parts.
first, last = re.findall("\D+", txt)
print((first, last))
('Salvatore', 'Abdulla')
Option-2
If you would (for some reason) also want to keep track of the number in between:
first, num, last = re.findall("(\D+)(\d{2})(\D+)", txt)
print((first, num, last))
('Salvatore', '32', 'Abdulla')
Option-3
As an extension of Option-2 and considering the text with a form 'Salvatore####...###Abdulla', where ####...### denotes a continuous block of digits separating the non-numeric parts and you may or may not have any idea of how many digits could be in-between, you could use the following:
first, num, last = re.findall("(\D+)(\d*)(\D+)", txt)
print((first, num, last))
('Salvatore', '32', 'Abdulla')

Why am I not getting the expected results?
You currently have one issue with your regex and one with your code.
Your regex contains ^, which anchors it to the start of the string. This will only allow you to match Salvatore. You're using findall (which is the appropriate choice if you change the regex to simply \D+), but right now it's only getting one result.
The second re.search call is not needed as you can capture first and last with the findall given an appropriate pattern (see below).
How do I fix it?
See code in use here
import re
txt = "Salvatore32Abdulla"
x = re.findall("\D+", txt)
print(x)
Result:
['Salvatore', 'Abdulla']

You could use a regex like this:
txt = "Salvatore32Abdulla"
regex = r"(\D+)\d\d(\D+)"
match = re.match(regex, txt)
first = match.group(1)
last = match.group(2)

Part after last digit:
match = re.search(r'\D+$',txt)
if match:
print(match.group())
See Python proof | regex proof.
Results: Abdulla
EXPLANATION
--------------------------------------------------------------------------------
\D+ non-digits (all but 0-9) (1 or more times
(matching the most amount possible))
--------------------------------------------------------------------------------
$ before an optional \n, and the end of the
string

Python regex to match after the text and the dot [duplicate]

I am using Python and would like to match all the words after test till a period (full-stop) or space is encountered.
text = "test : match this."
At the moment, I am using :
import re
re.match('(?<=test :).*',text)
The above code doesn't match anything. I need match this as my output.

Everything after test, including test
test.*
Everything after test, without test
(?<=test).*
Example here on regexr.com

You need to use re.search since re.match tries to match from the beging of the string. To match until a space or period is encountered.
re.search(r'(?<=test :)[^.\s]*',text)
To match all the chars until a period is encountered,
re.search(r'(?<=test :)[^.]*',text)

In a general case, as the title mentions, you may capture with (.*) pattern any 0 or more chars other than newline after any pattern(s) you want:
import re
p = re.compile(r'test\s*:\s*(.*)')
s = "test : match this."
m = p.search(s) # Run a regex search anywhere inside a string
if m: # If there is a match
print(m.group(1)) # Print Group 1 value
If you want . to match across multiple lines, compile the regex with re.DOTALL or re.S flag (or add (?s) before the pattern):
p = re.compile(r'test\s*:\s*(.*)', re.DOTALL)
p = re.compile(r'(?s)test\s*:\s*(.*)')
However, it will retrun match this.. See also a regex demo.
You can add \. pattern after (.*) to make the regex engine stop before the last . on that line:
test\s*:\s*(.*)\.
Watch out for re.match() since it will only look for a match at the beginning of the string (Avinash aleady pointed that out, but it is a very important note!)
See the regex demo and a sample Python code snippet:
import re
p = re.compile(r'test\s*:\s*(.*)\.')
s = "test : match this."
m = p.search(s) # Run a regex search anywhere inside a string
if m: # If there is a match
print(m.group(1)) # Print Group 1 value
If you want to make sure test is matched as a whole word, add \b before it (do not remove the r prefix from the string literal, or '\b' will match a BACKSPACE char!) - r'\btest\s*:\s*(.*)\.'.

I don't see why you want to use regex if you're just getting a subset from a string.
This works the same way:
if line.startswith('test:'):
print(line[5:line.find('.')])
example:
>>> line = "test: match this."
>>> print(line[5:line.find('.')])
match this
Regex is slow, it is awkward to design, and difficult to debug. There are definitely occassions to use it, but if you just want to extract the text between test: and ., then I don't think is one of those occasions.
See: https://softwareengineering.stackexchange.com/questions/113237/when-you-should-not-use-regular-expressions
For more flexibility (for example if you are looping through a list of strings you want to find at the beginning of a string and then index out) replace 5 (the length of 'test:') in the index with len(str_you_looked_for).

Using Regex to extract a specific word followed by certain syntax (such as parentheses)

I have a very large document containing section references in different formats. I want to extract these references using Python & regex.
Examples of the string formats:
1) Section 23
2) Section 45(3)
3) point (e) of Section 75
4) Sections 21(1), 54(2), 78(1)
Right now, I have the following code:
s = "This is a sample for Section 231"
m = re.search('Section\\W+(\\w+)', s)
m.group(0)
The output is: Section 231
This works perfectly, except that it does not account for the other formatting cases.
Is there any way to indicate that for 231(1), the (1) should also be extracted? Or to include the following section numbers if several others are listed?
I'm also open to using other libraries if you think Regex is not the best in this case. Thank you!

Try:
Sections?\W+(\w+)(\(\w+\))?(, (\w+)(\(\w+\))?)*
Demo
>>> s = 'Sections 21(1), 54(2), 78(1)'
>>> res = re.search(r'Sections?\W+(\w+)(\(\w+\))?(, (\w+)(\(\w+\))?)*', s)
>>> res.group(0)
# => 'Sections 21(1), 54(2), 78(1)'
Explanation:
Sections? matches "Section" with optionable s
\W+(\w+)(\(\w+\))? matches section number/title (as you did it) and adds optional text in brackets
(, (\w+)(\(\w+\))?)* allows repetition of the section number patter after comma and space
EDIT
To exclude Section 1 of Other Book you can use combination of word boundary and negative lookahead:
Sections?\W+(\w+)(\(\w+\))?(, (\w+)(\(\w+\))?)*\b(?! of)
Demo
\b assures that you match until end of a word
(?! of) check that after the word boundary there is no space followed by of

There's probably never going to be a catch-all regex for this - however the following is quite close to what you want:
Sections?( *\d+((\(\d+\))*,?(?= *))*)+
Sections? = Section or Sections
( *\d+((\(\d+\))*,?(?= *))*)+ = 1 or more of: 0 or more spaces, then 1 or more digits, optionally followed by 1 or more digits in braces, then optionally a comma and 0 or spaces.
The 'trailing' space uses a positive lookahead so it isn't included in the match, so you don't need to strip trailing spaces.
Try it out