正则表达式将主题标签拆分为单词

Question

I am trying to come up with a regex which will correctly split a hashtag into its words. For example:

XP => XP
ACar => A Car
GoodCar => Good Car
OnceUponATime => Once Upon A Time
LoveXP => Love XP
AppleVsXP => Apple Vs XP
JamesBond007 => James Bond 007

Edit: I have tried

expanded = ' '.join(re.findall(r"[A-Z][^A-Z]*", self.text))

What is aa more robust way which will address all the use cases above?

Answer 1

you can simply do this by this expression, it's totally sufficient:

expanded = " ".join([a for a in re.split('([A-Z][a-z]+)', i) if a])

it gives the following results:

XP
A Car
Good Car
Once Upon A Time
Love XP
Apple Vs XP
James Bond 007

Hope this was helpful.

Answer 2

You can define several patterns to match what's considered a separate word - an uppercase character followed by a series of lowercase characters, a series of digits, a series of uppercase characters not followed by lowercase characters, etc. - and then just cycle it over your string:

import re

pattern = re.compile(r"[A-Z][a-z]+|\d+|[A-Z]+(?![a-z])")

def split_hashtag(tag):
    return pattern.findall(tag)

If you test it with your tags:

test_tags = ["XP", "ACar", "GoodCar", "OnceUponATime", "LoveXP", "AppleVsXP", "JamesBond007"]
for tag in test_tags:
    print("{} => {}".format(tag, " ".join(split_hashtag(tag))))

You get:

XP => XP
ACar => A Car
GoodCar => Good Car
OnceUponATime => Once Upon A Time
LoveXP => Love XP
AppleVsXP => Apple Vs XP
JamesBond007 => James Bond 007