Eliminating series of .replace() calls in Python

Question

I'm working on a project that involves parsing pages of text. I've written the following function to remove certain punctuation from a word and convert it to lowercase:

def format_word(word):
    return word.replace('.', '').replace(',', '').replace('\"', '').lower()

Is there any way to combine all of the calls to .replace() into one? This looks rather ugly the way it is! The only way I can think of doing it is as follows:

def format_word(word):
    for punct in '.,\"':
        word.replace(punct, '')
    return word.lower()

unrelated: you don't need to escape `"` inside `'` string literals. — jfs, Jan 06 '15 at 08:41
related: [Best way to strip punctuation from a string in Python](http://stackoverflow.com/q/265960/4279) — jfs, Jan 06 '15 at 08:45
related: [Remove punctuation from Unicode formatted strings](http://stackoverflow.com/q/11066400/4279) — jfs, Jan 06 '15 at 08:45

score 8 · Accepted Answer · edited Jan 06 '15 at 08:36

8

You can use str.translate if you want to remove characters:

In python 2.x:

>>> 'Hello, "world".'.translate(None, ',."')
'Hello world'

In python 3.x:

>>> 'Hello, "world".'.translate(dict.fromkeys(map(ord, ',."')))
'Hello world'

edited Jan 06 '15 at 08:36

glglgl

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answered Jan 06 '15 at 08:33

falsetru

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upvote. You could also emulate `.lower()` in the same `.translate()` call. – jfs Jan 06 '15 at 08:42
[code example that shows how to use `translate()` to emulate `lower()` for ascii data](http://ideone.com/VpW59X) – jfs Jan 06 '15 at 08:59

nu11p01n73R · Answer 2 · 2015-01-06T10:37:14.623

4

You can use the re module for that

import re
>>> def format_word(word):
...     return re.sub(r'[,."]', "", word)
...
>>> print format_word('asdf.,"asdf')
asdfsdf

edited Jan 06 '15 at 10:37

answered Jan 06 '15 at 08:34

nu11p01n73R

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You seem to be missing a `'` after your regular expression. It should be `r'[,."]'`. – Niels Abildgaard Jan 06 '15 at 09:37
@NielsAbildgaard Corrected. Thank you – nu11p01n73R Jan 06 '15 at 10:37

score 0 · Answer 3 · answered Jan 06 '15 at 08:32

0

You are quite close. If you don't only call .replace(), but as well use its result, you are done:

def format_word(word):
    for punct in '.,\"':
        word = word.replace(punct, '')
    return word.lower()

answered Jan 06 '15 at 08:32

glglgl

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Not an answer to the question of avoiding multiple calls to `replace`. – Niels Abildgaard Jan 06 '15 at 09:32

score 0 · Answer 4 · answered Jan 06 '15 at 08:36

0

You can do this using regular expressions:

re.sub("[.,\"]", "", "\"wo,rd.")

answered Jan 06 '15 at 08:36

bigblind

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Eliminating series of .replace() calls in Python

4 Answers4