How to chain multiple re.sub() commands in Python

Question

I would like to do multiple re.sub() replacements on a string and I'm replacing with different strings each time.

This looks so repetitive when I have many substrings to replace. Can someone please suggest a nicer way to do this?

stuff = re.sub('__this__', 'something', stuff)
stuff = re.sub('__This__', 'when', stuff)
stuff = re.sub(' ', 'this', stuff)
stuff = re.sub('.', 'is', stuff)
stuff = re.sub('__', 'different', stuff).capitalize()

@Rawing, cool thanks that's better. My search wasn't showing that since I had re.sub(). Will delete. — JTFouquier, Sep 20 '17 at 17:50
Wait, actually should I keep this q since it's worded differently or delete it because it's a duplicate? — JTFouquier, Sep 20 '17 at 17:51
Honestly, I don't think it's worth keeping. But if you don't want to delete it, you can also close it as a duplicate. — Aran-Fey, Sep 20 '17 at 17:54
@JTFouquier See also https://stackoverflow.com/questions/5668947/use-pythons-string-replace-vs-re-sub — mkrieger1, Sep 20 '17 at 17:56
Yes, I will just use str.replace() instead. SO won't let me close this. ha. — JTFouquier, Sep 20 '17 at 17:59

mkrieger1 · Accepted Answer · 2021-02-24T13:21:29.040

31

Store the search/replace strings in a list and loop over it:

replacements = [
    ('__this__', 'something'),
    ('__This__', 'when'),
    (' ', 'this'),
    ('.', 'is'),
    ('__', 'different')
]

for old, new in replacements:
    stuff = re.sub(old, new, stuff)

stuff = stuff.capitalize()

Note that when you want to replace a literal . character you have to use '\.' instead of '.'.

edited Feb 24 '21 at 13:21

answered Sep 20 '17 at 17:45

mkrieger1

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3

I'm assuming it has been defined before, just like in the original code. – mkrieger1 Sep 20 '17 at 17:47
But `re.sub` hasn't been called before. `stuff` is just the original string at the beginning. – mkrieger1 Sep 20 '17 at 17:53
Ah, your right. I misread the OP's post. For some reason my brain replaced "stuff" with "string" ... and _now_ looking back at my answer, I still see it was pretty dumb. For the OP's use case, yours is clearly better. Sorry about that. – Christian Dean Sep 20 '17 at 17:56

score 3 · Answer 2 · answered Sep 20 '17 at 17:48

3

tuple = (('__this__', 'something'),('__This__', 'when'),(' ', 'this'),('.', 'is'),('__', 'different'))

for element in tuple:
    stuff = re.sub(element[0], element[1], stuff)

answered Sep 20 '17 at 17:48

Rômulo Tone

115
6

How to chain multiple re.sub() commands in Python

2 Answers2