separate certain characters when matched from either direction regex python

Question

I have something like this:

text = "hey;)there"

Need this:

text = "hey ;) there"

I am doing 2 passes:

op_1 = re.sub(r'([a-zA-Z])([:;()])', r'\1 \2', text)
final_result = re.sub(r'([:;()])([a-zA-Z])', r'\1 \2', op_1)

I am sure there must be an efficient way for this.

Could you be more explicit about the cases you do and don't want to handle? What's the actual task here? — jonrsharpe
– jonrsharpe, Commented Jun 24, 2016 at 10:44
just want to separate a few characters that don't match '\w', say for emoticons — Kevad
– Kevad, Commented Jun 24, 2016 at 10:48
In that case, would r'(\W{2,})' do it? Then you can just replace it with r' \1 ' - regex101.com/r/kM4qZ9/1 — jonrsharpe
– jonrsharpe, Commented Jun 24, 2016 at 10:48
Note the regex should be {2} for "precisely two" or {2,} for "at least two". :, - and ) are all matched by \W. — jonrsharpe
– jonrsharpe, Commented Jun 24, 2016 at 13:19

rock321987 · Accepted Answer · 2016-06-24 10:47:48Z

1

You can use lookaheads and lookbehinds with alternation

>>> re.sub('(?<=[a-zA-Z])(?=[:;()])|(?<=[:;()])(?=[a-zA-Z])', ' ', text)
'hey ;) there'

Regex Breakdown

(?<=[a-zA-Z]) #Lookbehind to match an alphabet
(?=[:;()]) #Lookahead to match the position of signs
| Alternation(OR)
(?<=[:;()]) #Lookbehind to match the position of signs
(?=[a-zA-Z]) #Lookahead to match an alphabet

edited Jun 24, 2016 at 10:47

answered Jun 24, 2016 at 10:38

rock321987

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8 Comments

Kevad Over a year ago

the result is not the same. :) a couple of characters are missing. I just want to separate the pattern.

jonrsharpe Over a year ago

Note that you can include explanations inline if you use triple-quoted r"""raw strings""" and the re.VERBOSE flag, often handy for keeping the information with the code.

rock321987 Over a year ago

@Kevad what characters are missing?

Kevad Over a year ago

I need 'hey ;) there', the above snippet gives 'he ;) here'

rock321987 Over a year ago

@Kevad as you wish..you can use \W{2} for non-word character..feel free to give an upvote..:)

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