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Find and Replace Simplification for Python code

0 votes
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I have some code that I want to simplify. I know that a for-loop would work well, but can I make re.sub perform all of the below tasks at once, or can I write this in a way that is more efficient than using a for-loop?

DATA = re.sub(',', '', 'DATA')
DATA = re.sub(''', '', 'DATA')
DATA = re.sub('(', '', 'DATA')
DATA = re.sub(')', '', 'DATA')

posted Jul 19, 2013 by anonymous

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Try DATA = re.sub(r'[(,\)]', '', 'DATA')

2 Answers

+1 vote
 
Best answer

I don't think you intended to put DATA in quotes on the right hand side. That makes it literally the string D A T A, so all those replacements are no-ops, and you could simplify it to:

DATA = 'DATA'

But that's probably not what you wanted.

My prediction is that this will be by far the most efficient way to do what you are trying to do:

py> DATA = "Hello, 'World'()"
py> DATA.translate(dict.fromkeys(ord(c) for c in ",'()"))
'Hello World'

That's in Python 3 -- in Python 2, using translate will still probably be the fastest, but you'll need to call it like this:

import string
DATA.translate(string.maketrans("", ""), ",'()")

I also expect that the string replace() method will be second fastest, and re.sub will be the slowest, by a very long way.

As a general rule, you should avoiding using regexes unless the text you are searching for actually contains a regular expression of some kind. If it's merely a literal character or substring, standard string methods will probably be faster.

a tip for you:

- don't escape quotes unless you don't need to, use the other quote.
s = ''' # No, don't do this!
s = "'" # Better!
and vice versa.
answer Jul 19, 2013 by anonymous
0 votes

If your actual use-case is this simple, you might want to use one of the built-in string functions such as strip() or translate().

answer Jul 19, 2013 by anonymous
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