从Python中删除字符串标点符号的最佳方法

时间:2008-11-05 17:30:32

标签: python string punctuation

似乎应该有一个比以下更简单的方法:

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

有吗?

31 个答案:

答案 0 :(得分:731)

从效率的角度来看,你不会打败

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))

它正在使用查找表在C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。

如果速度不是担心,另一个选择是:

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

这比使用每个char的s.replace更快,但是不能像非纯python方法那样运行,例如正则表达式或string.translate,正如您可以从下面的时间中看到的那样。对于这种类型的问题,尽可能低的水平做到这一点是值得的。

时间码:

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)

这给出了以下结果:

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

答案 1 :(得分:107)

正则表达式很简单,如果你知道的话。

import re
s = "string. With. Punctuation?"
s = re.sub(r'[^\w\s]','',s)

在上面的代码中,我们用空字符串替换(re.sub)所有NON [字母数字字符(\ w)和空格(\ s)]。
因此。和?通过正则表达式运行s变量后,变量's'中不会出现标点符号。

答案 2 :(得分:58)

为了方便使用,我总结了Python 2和Python 3中字符串条带化标点符号的注释。请参阅其他答案以获取详细说明。

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({key: None for key in string.punctuation})
new_s = s.translate(table)                          # Output: string without punctuation

答案 3 :(得分:51)

myString.translate(None, string.punctuation)

答案 4 :(得分:25)

我通常使用这样的东西:

>>> s = "string. With. Punctuation?" # Sample string
>>> import string
>>> for c in string.punctuation:
...     s= s.replace(c,"")
...
>>> s
'string With Punctuation'

答案 5 :(得分:22)

string.punctuation仅为ASCII !更正确(但也更慢)的方法是使用unicodedata模块:

# -*- coding: utf-8 -*-
from unicodedata import category
s = u'String — with -  «punctation »...'
s = ''.join(ch for ch in s if category(ch)[0] != 'P')
print 'stripped', s

答案 6 :(得分:21)

如果你对这个家庭更熟悉的话,不一定更简单,但不一样。

import re, string
s = "string. With. Punctuation?" # Sample string 
out = re.sub('[%s]' % re.escape(string.punctuation), '', s)

答案 7 :(得分:12)

对于Python 3 str或Python 2 unicode值,str.translate()只接受字典;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() class method使创建映射变得微不足道,根据键序列将所有值设置为None

要删除所有标点符号,而不仅仅是ASCII标点符号,您的表格需要更大一些;见J.F. Sebastian's answer(Python 3版):

import unicodedata
import sys

remove_punct_map = dict.fromkeys(i for i in range(sys.maxunicode)
                                 if unicodedata.category(chr(i)).startswith('P'))

答案 8 :(得分:12)

string.punctuation错过了现实世界中常用的标点符号。如何使用适用于非ASCII标点符号的解决方案?

import regex
s = u"string. With. Some・Really Weird、Non?ASCII。 「(Punctuation)」?"
remove = regex.compile(ur'[\p{C}|\p{M}|\p{P}|\p{S}|\p{Z}]+', regex.UNICODE)
remove.sub(u" ", s).strip()

就个人而言,我认为这是从Python中删除字符串标点符号的最佳方法,因为:

  • 删除所有Unicode标点符号
  • 它很容易修改,例如如果您要删除标点符号,可以删除\{S},但请保留$之类的符号。
  • 您可以真正了解要保留的内容以及要删除的内容,例如\{Pd}只会删除破折号。
  • 这个正则表达式也规范了空白。它将标签,回车和其他奇怪的地方映射到漂亮的单一空间。

这使用Unicode字符属性,you can read more about on Wikipedia

答案 9 :(得分:6)

这可能不是最佳解决方案,但这就是我的方法。

import string
f = lambda x: ''.join([i for i in x if i not in string.punctuation])

答案 10 :(得分:6)

这是我写的一个函数。这不是很有效,但它很简单,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

答案 11 :(得分:6)

这是Python 3.5的单行代码:

import string
"l*ots! o(f. p@u)n[c}t]u[a'ti\"on#$^?/".translate(str.maketrans({a:None for a in string.punctuation}))

答案 12 :(得分:6)

我还没有看到这个答案。只需使用正则表达式;它会删除除字符(\w)和数字字符(\d)之外的所有字符,后跟空格字符(\s):

import re
s = "string. With. Punctuation?" # Sample string 
out = re.sub(ur'[^\w\d\s]+', '', s)

答案 13 :(得分:4)

就像更新一样,我在Python 3中重写了@Brian示例并对其进行了更改以在函数内部移动正则表达式编译步骤。我的想法是为了使功能发挥作用所需的每一步。也许您正在使用分布式计算,并且不能在您的工作人员之间共享正则表达式对象,并且需要在每个工作人员处执行re.compile步骤。另外,我很想为Python 3的两个不同的maketrans实现计时

table = str.maketrans({key: None for key in string.punctuation})

vs

table = str.maketrans('', '', string.punctuation)

另外我添加了另一种使用set的方法,其中我利用交集函数来减少迭代次数。

这是完整的代码:

import re, string, timeit

s = "string. With. Punctuation"


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


def test_set2(s):
    _punctuation = set(string.punctuation)
    for punct in set(s).intersection(_punctuation):
        s = s.replace(punct, ' ')
    return ' '.join(s.split())


def test_re(s):  # From Vinko's solution, with fix.
    regex = re.compile('[%s]' % re.escape(string.punctuation))
    return regex.sub('', s)


def test_trans(s):
    table = str.maketrans({key: None for key in string.punctuation})
    return s.translate(table)


def test_trans2(s):
    table = str.maketrans('', '', string.punctuation)
    return(s.translate(table))


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("sets2      :",timeit.Timer('f(s)', 'from __main__ import s,test_set2 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("translate2 :",timeit.Timer('f(s)', 'from __main__ import s,test_trans2 as f').timeit(1000000))
print("replace   :",timeit.Timer('f(s)', 'from __main__ import s,test_repl as f').timeit(1000000))

这是我的结果:

sets      : 3.1830138750374317
sets2      : 2.189873124472797
regex     : 7.142953420989215
translate : 4.243278483860195
translate2 : 2.427158243022859
replace   : 4.579746678471565

答案 14 :(得分:4)

这是一个没有正则表达式的解决方案。

import string

input_text = "!where??and!!or$$then:)"
punctuation_replacer = string.maketrans(string.punctuation, ' '*len(string.punctuation))    
print ' '.join(input_text.translate(punctuation_replacer).split()).strip()

Output>> where and or then
  • 用空格替换标点符号
  • 用单个空格替换单词之间的多个空格
  • 删除尾随空格(如果有) 条()

答案 15 :(得分:3)

import re
s = "string. With. Punctuation?" # Sample string 
out = re.sub(r'[^a-zA-Z0-9\s]', '', s)

答案 16 :(得分:3)

>>> s = "string. With. Punctuation?"
>>> s = re.sub(r'[^\w\s]','',s)
>>> re.split(r'\s*', s)


['string', 'With', 'Punctuation']

答案 17 :(得分:2)

在非常严格的情况下,单行可能会有所帮助:

''.join([c for c in s if c.isalnum() or c.isspace()])

答案 18 :(得分:2)

尝试一个:)

regex.sub(r'\p{P}','', s)

答案 19 :(得分:2)

这是使用RegEx进行操作的另一种简便方法

$joined_path2=Join-Path -LiteralPath '\\?\UNC\' -ChildPath $joined_path

答案 20 :(得分:1)

我一直在寻找一个非常简单的解决方案。这是我得到的:

import re 

s = "string. With. Punctuation?" 
s = re.sub(r'[\W\s]', ' ', s)

print(s)
'string  With  Punctuation '

答案 21 :(得分:1)

使用正则表达式函数进行搜索和替换,如here.所示。如果你必须重复执行操作,你可以保留正则表达式模式(你的标点符号)的编译副本,这会加快速度。

答案 22 :(得分:1)

with open('one.txt','r')as myFile:

    str1=myFile.read()

    print(str1)


    punctuation = ['(', ')', '?', ':', ';', ',', '.', '!', '/', '"', "'"] 

for i in punctuation:

        str1 = str1.replace(i," ") 
        myList=[]
        myList.extend(str1.split(" "))
print (str1) 
for i in myList:

    print(i,end='\n')
    print ("____________")

答案 23 :(得分:1)

#FIRST METHOD
#Storing all punctuations in a variable    
punctuation='!?,.:;"\')(_-'
newstring='' #Creating empty string
word=raw_input("Enter string: ")
for i in word:
     if(i not in punctuation):
                  newstring+=i
print "The string without punctuation is",newstring

#SECOND METHOD
word=raw_input("Enter string: ")
punctuation='!?,.:;"\')(_-'
newstring=word.translate(None,punctuation)
print "The string without punctuation is",newstring


#Output for both methods
Enter string: hello! welcome -to_python(programming.language)??,
The string without punctuation is: hello welcome topythonprogramminglanguage

答案 24 :(得分:0)

为什么你们都不使用这个?

 ''.join(filter(str.isalnum, s)) 

太慢了吗?

答案 25 :(得分:0)

考虑unicode。代码已在python3中检查。

df = (df.rename(columns = lambda x: x.replace('_x', ''))
        .fillna(df.filter(regex='_y$')
                  .rename(columns = lambda x: x.replace('_y', '')))
        .filter(regex=r'.*(?<!_y)$'))
print (df)
    A    B    C
0  R1  0.0  6.0
1  R2  4.0  8.0
2  R3  2.0  2.0

答案 26 :(得分:0)

您也可以这样做:

import string
' '.join(word.strip(string.punctuation) for word in 'text'.split())

答案 27 :(得分:-1)

这是如何将我们的文档更改为大写 或小写。

print('@@@@This is lower case@@@@')

with open('students.txt','r')as myFile:

    str1=myFile.read()
    str1.lower()
print(str1.lower())

print('*****This is upper case****')

with open('students.txt','r')as myFile:

    str1=myFile.read()

    str1.upper()

print(str1.upper())

答案 28 :(得分:-1)

使用Python

从文本文件中删除停用词
print('====THIS IS HOW TO REMOVE STOP WORS====')

with open('one.txt','r')as myFile:

    str1=myFile.read()

    stop_words ="not", "is", "it", "By","between","This","By","A","when","And","up","Then","was","by","It","If","can","an","he","This","or","And","a","i","it","am","at","on","in","of","to","is","so","too","my","the","and","but","are","very","here","even","from","them","then","than","this","that","though","be","But","these"

    myList=[]

    myList.extend(str1.split(" "))

    for i in myList:

        if i not in stop_words:

            print ("____________")

            print(i,end='\n')

答案 29 :(得分:-1)

def punctuationRemover(p):
'''
    Input: Takes a string. You may have to use str() to force it. 
    Removes all punctuation.
    Output: Returns a string.
'''
    punctuations = '''!()-[]{};:'"\,<>./?@#$%^&*_~'''
    no_punctuations = ''

    for words in p: # You may not have to loop this high
        for char in p:
            if char not in punctuations:
                no_punctuations = no_punctuations + char

return(no_punctuations)

答案 30 :(得分:-2)

我喜欢使用这样的函数:

def scrub(abc):
    while abc[-1] is in list(string.punctuation):
        abc=abc[:-1]
    while abc[0] is in list(string.punctuation):
        abc=abc[1:]
    return abc