如果您正在使用python2并且您的输入是字符串(不是unicodes)，那么绝对最好的方法是remove_chars_translate_bytes：

>>> chars_to_remove = ['.', '!', '?']

>>> subj = 'A.B!C?'

>>> subj.translate(None, ''.join(chars_to_remove))

'ABC'

否则，有以下选项可供考虑：

A.通过char迭代主题char，省略不需要的字符和结果列表remove_chars_translate_bytes：

>>> sc = set(chars_to_remove)

>>> ''.join([c for c in subj if c not in sc])

'ABC'

(请注意，生成器版本remove_chars_translate_bytes效率较低)。

B.动态创建正则表达式，并使用空字符串创建remove_chars_translate_bytes：

>>> import re

>>> rx = '[' + re.escape(''.join(chars_to_remove)) + ']'

>>> re.sub(rx, '', subj)

'ABC'

(remove_chars_translate_bytes确保像remove_chars_translate_bytes或]这样的字符不会破坏正则表达式)。

C.使用remove_chars_translate_bytes的映射变体：

>>> chars_to_remove = [u'δ', u'Γ', u'ж']

>>> subj = u'AжBδCΓ'

>>> dd = {ord(c):None for c in chars_to_remove}

>>> subj.translate(dd)

u'ABC'

完整的测试代码和时间：

#coding=utf8

import re

def remove_chars_iter(subj, chars):

sc = set(chars)

return ''.join([c for c in subj if c not in sc])

def remove_chars_re(subj, chars):

return re.sub('[' + re.escape(''.join(chars)) + ']', '', subj)

def remove_chars_re_unicode(subj, chars):

return re.sub(u'(?u)[' + re.escape(''.join(chars)) + ']', '', subj)

def remove_chars_translate_bytes(subj, chars):

return subj.translate(None, ''.join(chars))

def remove_chars_translate_unicode(subj, chars):

d = {ord(c):None for c in chars}

return subj.translate(d)

import timeit, sys

def profile(f):

assert f(subj, chars_to_remove) == test

t = timeit.timeit(lambda: f(subj, chars_to_remove), number=1000)

print ('{0:.3f} {1}'.format(t, f.__name__))

print (sys.version)

PYTHON2 = sys.version_info[0] == 2

print ('\n"plain" string:\n')

chars_to_remove = ['.', '!', '?']

subj = 'A.B!C?' * 1000

test = 'ABC' * 1000

profile(remove_chars_iter)

profile(remove_chars_re)

if PYTHON2:

profile(remove_chars_translate_bytes)

else:

profile(remove_chars_translate_unicode)

print ('\nunicode string:\n')

if PYTHON2:

chars_to_remove = [u'δ', u'Γ', u'ж']

subj = u'AжBδCΓ'

else:

chars_to_remove = ['δ', 'Γ', 'ж']

subj = 'AжBδCΓ'

subj = subj * 1000

test = 'ABC' * 1000

profile(remove_chars_iter)

if PYTHON2:

profile(remove_chars_re_unicode)

else:

profile(remove_chars_re)

profile(remove_chars_translate_unicode)

结果：

2.7.5 (default, Mar 9 2014, 22:15:05)

[GCC 4.2.1 Compatible Apple LLVM 5.0 (clang-500.0.68)]

"plain" string:

0.637 remove_chars_iter

0.649 remove_chars_re

0.010 remove_chars_translate_bytes

unicode string:

0.866 remove_chars_iter

0.680 remove_chars_re_unicode

1.373 remove_chars_translate_unicode

---

3.4.2 (v3.4.2:ab2c023a9432, Oct 5 2014, 20:42:22)

[GCC 4.2.1 (Apple Inc. build 5666) (dot 3)]

"plain" string:

0.512 remove_chars_iter

0.574 remove_chars_re

0.765 remove_chars_translate_unicode

unicode string:

0.817 remove_chars_iter

0.686 remove_chars_re

0.876 remove_chars_translate_unicode

(作为旁注，remove_chars_translate_bytes的数字可能会给我们一个线索，为什么业界不愿意长期采用Unicode)。