Special regex for String in python

Question

I have a string like below.

s = ({[test1, test2 ; test3 (New) ]})

Now I have a regex which will remove brackets and convert it into the list. Even if there are separated with a;b,c like. REGEX:

output = [i for i in re.split(r'\s*[(){}<>\[\],;\'"]\s*', s) if i]

But this regex is removing brackets from items of the list as well. ((New) in my case)

How to apply this regex for beginnig and end of the string. I know it can be done using ^ but not sure how?

Expected Output

['test1', 'test2', 'test3 (New)' ]

Output coming from above regex

['test1', 'test2', 'test3', 'New']

Any help?

Is adding the brackets to the list element an option ? Is the (New) element always the last in the list ? — David
– David, Commented May 22, 2018 at 9:10
No, I mean there may be (New) something like this in any element of my string. I want to remove brackets only from starting and end of string — Jayesh Dhandha
– Jayesh Dhandha, Commented May 22, 2018 at 9:12
@JayeshDhandha, what should be the result for this string -[({[test1, test2(3) ; test3 (New) ]})]-? — RomanPerekhrest
– RomanPerekhrest, Commented May 22, 2018 at 9:32

SpghttCd · Accepted Answer · 2018-05-22 11:16:42Z

1

s = '({[test1, test2 ; test3 (New) ]})'

Based on your comment below I assume that the number of opening brackets of the whole string is equal to the number of closing brackets.

So removing the outer brackets first needs to know their number:

m = re.match('[({[]*', s)
n_brckt = m.span()[1] - m.span()[0]

Then remove the outer brackets ( - dependent on if there were found any...):

if n_brckt > 0:
    s = s[n_brckt:-n_brckt]
s = s.strip()

In: s
Out: 'test1, test2 ; test3 (New)'

Then you can split at all occurences of commas or colons optionally followed by a space:

In: re.split('[,;]+ *', s)
Out: ['test1', 'test2', 'test3 (New)']

edited May 22, 2018 at 11:16

answered May 22, 2018 at 9:13

SpghttCd

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6 Comments

Jayesh Dhandha Over a year ago

I can't use strip as there may be different number of brackets in the starting and ending of string. I can't use string with 3 count

SpghttCd Over a year ago

So how do the beginning and the end of the strings look like? This should be made clear, otherwise it's just a guessing game...

Jayesh Dhandha Over a year ago

Its not fix. Sometimes it has [{( and sometimes [{ only. And same thing at the end of string.

Jayesh Dhandha Over a year ago

You have missed 1 thing. If my string doesn't contain any brackets then your output will be [''] Which is not right.

SpghttCd Over a year ago

Do you want to tell me, that the string might even have no outer brackets at all...?

|

Rakesh · Accepted Answer · 2018-05-22 10:05:48Z

1

Using re.search

import re
s = "({[test1, test2 ; test3 (New) ]})"
m = re.search("\[(.*?)\]", s)
if m:
    #print(m.group(1).replace(";", ",").split(",")) 
    print([i.strip() for i in m.group(1).replace(";", ",").split(",")])

Output:

['test1', 'test2', 'test3 (New)']

answered May 22, 2018 at 10:05

Rakesh

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4 Comments

Jayesh Dhandha Over a year ago

Good Answer. Thanks!

Jayesh Dhandha Over a year ago

Check output for (({{[[test1, test2 ; test3 (France)]]}}))

Rakesh Over a year ago

For a deep nested structure, regex will not work and can cause unwanted issues. It is best to find a parser according to your need. Ex: stackoverflow.com/questions/5454322/…

SpghttCd Over a year ago

Please note that if m: is not a valid test for success of re.match. You could use if m.end(): but however, clearly writing if m.end() > 0: or sth similar is always clearer to read and understand immediately.

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