Regex - Replace dots within bracket

Question

I need to replace dots within brackets with re with another string:

from

a = 'hello.mate(how.are.you)'

to

b = 'hello.mate(how|DOT|are|DOT|you)

I tried to use /( to highlight the beginning of the brackets and /) for the closing, but I am unclear how to capture the simple dot in between.

The two most pertinent examples

These two questions clearly faced the exact same problem, expecially question #2, but I can't seem to capture just a single dot in the re.sub

Regex replace text between delimiters in python

Regex using Python to replace dot of floating numbers with "dot"

Attempted solutions

Various ineffective attempts based on the examples above include:

b = re.sub(r'\(.\)','|DOT|', a)
b = re.sub(r'\(\.\)','|DOT|', a)
b = re.sub(r'\([.]\)','|DOT|', a)
b = re.sub(r'\([\.]\)','|DOT|', a)

Your problem is that you aren't allowing for anything to be between the "(" and the "." — Neil, Jun 11 '19 at 12:23
A usual workaround would do here - `re.sub(r'\.(?=[^()]*\))', '|DOT|', s)`. It won't work if the parentheses can be nested. — Wiktor Stribiżew, Jun 11 '19 at 12:45

score 7 · Accepted Answer · answered Jun 11 '19 at 12:23

7

You can nest re.sub to first match string inside brackets and then substitute . for |DOT|:

import re

a = 'hello.mate(how.are.you)'

s = re.sub(r'\((.*?)\)', lambda g: re.sub(r'\.', '|DOT|', g[0]), a)
print(s)

Prints:

hello.mate(how|DOT|are|DOT|you)

answered Jun 11 '19 at 12:23

Andrej Kesely

168,389
15
48
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Brilliant - a complication for you, what if I want to remove all dots OUTSIDE of parentheses? – Pythonic Jun 11 '19 at 12:27
This is a different question @Pythonic which should be posted separately – yatu Jun 11 '19 at 12:31
1

@Pythonic Just from the head, probably exists better solution: `s = re.sub(r'(.*)(\(.*?\))(.*)', lambda g: g[1].replace('.', '|DOT|') + g[2] + g[3].replace('.', '|DOT|'), a)` – Andrej Kesely Jun 11 '19 at 12:33
@AndrejKesely wouldnt a single re.sub with lookaheads be enough? – yatu Jun 11 '19 at 12:33
@yatu I'm not sure if that's possible. From my previous experience no, but I'm regex beginner. – Andrej Kesely Jun 11 '19 at 12:35
not with lookaheads, but i guess with capturing group. Tel me figure it out for a minute – user8426627 Jun 11 '19 at 12:40
This solution will fail if the parentheses can be nested. – Wiktor Stribiżew Jun 11 '19 at 12:48
@WiktorStribiżew In this case is the regex right tool to use? – Andrej Kesely Jun 11 '19 at 12:50
@AndrejKesely If you use PyPi regex module, it is. But you need the right pattern. – Wiktor Stribiżew Jun 11 '19 at 12:56

score 0 · Answer 2 · answered Jun 11 '19 at 12:52

I tryed something like :

import re




a = 'hello.mate(.are.you)'




res = r'\([^\.\)]*(?:(?P<dot>\.)[^\.\)]*)+\)'

p = re.compile(res)

for m in  re.finditer(p,  a):

    print(m.start('dot'), m.end('dot'))

but i do not understand why dot is only ones captured

Shubhankar Mohan · Answer 3 · 2019-06-11T16:47:28.133

0

Try this,

import re
a = 'hello.mate(how.are.you)'  
content_in_brackets = re.findall(r'\((.*?)\)', a)
for con in content_in_brackets:
    a = a.replace(con, con.replace('.', '|DOT|'))

edited Jun 11 '19 at 16:47

answered Jun 11 '19 at 13:04

Shubhankar Mohan

129
1
9

@WiktorStribiżew what output you are getting?? – Shubhankar Mohan Jun 11 '19 at 13:13
And [here your code fails](https://ideone.com/YSJYTP), it should not replace `.` NOT inside parentheses – Wiktor Stribiżew Jun 11 '19 at 13:20
I thought this was what we had to do, replace dot inside parentheses – Shubhankar Mohan Jun 11 '19 at 13:26
@WiktorStribiżew got your point. Thanks. I have edited my answer, let me know your review. – Shubhankar Mohan Jun 11 '19 at 16:47
It is working but I am not sure it is the best solution for the current problem. – Wiktor Stribiżew Jun 11 '19 at 20:00

Regex - Replace dots within bracket

3 Answers3