似乎应该有一种比以下更简单的方法:
import string
s = "string. With. Punctuation?" # Sample string
out = s.translate(string.maketrans("",""), string.punctuation)
有?
似乎应该有一种比以下更简单的方法:
import string
s = "string. With. Punctuation?" # Sample string
out = s.translate(string.maketrans("",""), string.punctuation)
有?
当前回答
显然,我无法对所选答案进行编辑,所以这里有一个适用于Python3的更新。在进行非平凡转换时,转换方法仍然是最有效的选择。
上面的@Brian为最初的繁重工作做出了贡献。感谢@ddejohn对原始测试的改进建议。
#!/usr/bin/env python3
"""Determination of most efficient way to remove punctuation in Python 3.
Results in Python 3.8.10 on my system using the default arguments:
set : 51.897
regex : 17.901
translate : 2.059
replace : 13.209
"""
import argparse
import re
import string
import timeit
parser = argparse.ArgumentParser()
parser.add_argument("--filename", "-f", default=argparse.__file__)
parser.add_argument("--iterations", "-i", type=int, default=10000)
opts = parser.parse_args()
with open(opts.filename) as fp:
s = fp.read()
exclude = set(string.punctuation)
table = str.maketrans("", "", string.punctuation)
regex = re.compile(f"[{re.escape(string.punctuation)}]")
def test_set(s):
return "".join(ch for ch in s if ch not in exclude)
def test_regex(s): # From Vinko's solution, with fix.
return regex.sub("", s)
def test_translate(s):
return s.translate(table)
def test_replace(s): # From S.Lott's solution
for c in string.punctuation:
s = s.replace(c, "")
return s
opts = dict(globals=globals(), number=opts.iterations)
solutions = "set", "regex", "translate", "replace"
for solution in solutions:
elapsed = timeit.timeit(f"test_{solution}(s)", **opts)
print(f"{solution:<10}: {elapsed:6.3f}")
其他回答
在不太严格的情况下,单行线可能会有所帮助:
''.join([c for c in s if c.isalnum() or c.isspace()])
对于Python 3 str或Python 2 unicode值,str.translate()只使用字典;在该映射中查找代码点(整数),并删除映射到None的任何内容。
要删除(某些?)标点符号,请使用:
import string
remove_punct_map = dict.fromkeys(map(ord, string.punctuation))
s.translate(remove_punct_map)
dict.fromkeys()类方法使创建映射变得简单,根据键的顺序将所有值设置为None。
要删除所有标点符号,而不仅仅是ASCII标点符号,您的表需要稍微大一点;参见J.F.Sebastian的答案(Python 3版本):
import unicodedata
import sys
remove_punct_map = dict.fromkeys(i for i in range(sys.maxunicode)
if unicodedata.category(chr(i)).startswith('P'))
为了方便使用,我总结了Python 2和Python 3中从字符串中删除标点符号的注意事项。有关详细说明,请参阅其他答案。
Python 2
import string
s = "string. With. Punctuation?"
table = string.maketrans("","")
new_s = s.translate(table, string.punctuation) # Output: string without punctuation
Python 3
import string
s = "string. With. Punctuation?"
table = str.maketrans(dict.fromkeys(string.punctuation)) # OR {key: None for key in string.punctuation}
new_s = s.translate(table) # Output: string without punctuation
从效率的角度来看,你不会击败
s.translate(None, string.punctuation)
对于更高版本的Python,请使用以下代码:
s.translate(str.maketrans('', '', string.punctuation))
它使用查找表在C语言中执行原始字符串操作——除了编写自己的C代码之外,没有什么能比这更好的了。
如果速度不令人担忧,另一个选择是:
exclude = set(string.punctuation)
s = ''.join(ch for ch in s if ch not in exclude)
这比用每个字符替换s.replace更快,但不会像正则表达式或字符串转换等非纯python方法那样执行得好,正如您从下面的计时中看到的那样。对于这种类型的问题,在尽可能低的水平上解决是有回报的。
计时代码:
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)
结果如下:
sets : 19.8566138744
regex : 6.86155414581
translate : 2.12455511093
replace : 28.4436721802
这是我写的一个函数。它不是很有效,但很简单,您可以添加或删除任何您想要的标点符号:
def stripPunc(wordList):
"""Strips punctuation from list of words"""
puncList = [".",";",":","!","?","/","\\",",","#","@","$","&",")","(","\""]
for punc in puncList:
for word in wordList:
wordList=[word.replace(punc,'') for word in wordList]
return wordList