Best way to strip punctuation from a string in Python
Question: It seems like there should be a simpler way than:

    
    
    import string
    s = "string. With. Punctuation?" # Sample string 
    out = s.translate(string.maketrans("",""), string.punctuation)
    

Is there?


Answer: From an efficiency perspective, you're not going to beat translate() - it's
performing raw string operations in C with a lookup table - there's not much
that will beat that but writing your own C code. If speed isn't a worry,
another option though is:

    
    
    exclude = set(string.punctuation)
    s = ''.join(ch for ch in s if ch not in exclude)
    

This is faster than s.replace with each char, but won't perform as well as
non-pure python approaches such as regexes or string.translate, as you can see
from the below timings. For this type of problem, doing it at as low a level
as possible pays off.

Timing code:

    
    
    import re, string, timeit
    
    s = "string. With. Punctuation"
    exclude = set(string.punctuation)
    table = string.maketrans("","")
    regex = re.compile('[%s]' % re.escape(string.punctuation))
    
    def test_set(s):
        return ''.join(ch for ch in s if ch not in exclude)
    
    def test_re(s):  # From Vinko's solution, with fix.
        return regex.sub('', s)
    
    def test_trans(s):
        return s.translate(table, string.punctuation)
    
    def test_repl(s):  # From S.Lott's solution
        for c in string.punctuation:
            s=s.replace(c,"")
        return s
    
    print "sets      :",timeit.Timer('f(s)', 'from __main__ import s,test_set as f').timeit(1000000)
    print "regex     :",timeit.Timer('f(s)', 'from __main__ import s,test_re as f').timeit(1000000)
    print "translate :",timeit.Timer('f(s)', 'from __main__ import s,test_trans as f').timeit(1000000)
    print "replace   :",timeit.Timer('f(s)', 'from __main__ import s,test_repl as f').timeit(1000000)
    

This gives the following results:

    
    
    sets      : 19.8566138744
    regex     : 6.86155414581
    translate : 2.12455511093
    replace   : 28.4436721802
    

