如何用空格替换标点符号

Question

punc_list = [".",";",":","!","?","/","\\",",","#","@","$","&",")","(","'","\""]
new_s = ''
for i in s:
    if i not in punc_list:
        new_s += i
return new_s.lower()

如果输入是

s = ("Hey! M'y nam;e i's")

我希望输出是：

s = ('hey  m y name e i s') 

我无法用空格替换 punc

Answer 1

当字符是标点符号时，您忘记添加空格' ' 。 此外， punc_list实际上不必是一个list ； 您可以将其设为一个长字符串并迭代字符，或者如注释中所述，只需使用string.punctuation 。 并且为了提高查找速度，您也可以将其set ，但在这种情况下它真的不重要：

punc_list = set('.;:!?/\\,#@$&)(\'"')  # or use string.punctuation

def no_punc(s):
    new_s = ''
    for i in s:
        if i not in punc_list:
            new_s += i
        else:
            new_s += ' '
    return new_s.lower()

或者更短一点，使用三元表达式... if ... else ... ：

def no_punc(s):
    new_s = ''
    for i in s:
        new_s += i if i not in punc_list else ' '
    return new_s.lower()

或者更短，使用str.join ：

def no_punc(s):
    return ''.join(i if i not in punc_list else ' ' for i in s).lower()

或者更短，使用正则表达式re ：

import re
def no_punc(s):
    return re.sub("\W", " ", s).lower()

Answer 2

使用str.translate 。 将punc_list中的所有字符转换为空格。

>>> punc_list = [".",";",":","!","?","/","\\",",","#","@","$","&",")","(","'","\""]
>>> s = "Hey! M'y nam;e i's"
>>> s.translate({ord(p): " " for p in punc_list})
'Hey  M y nam e i s'

您可以使用 dict comprehension 动态创建字典映射，它将所有标点字符代码（使用ord函数）映射到一个空格。

Answer 3

作业问题是否应该帮助您了解循环？ 我认为学习 dicts 和 translate 也很有用。

t = str.maketrans(dict.fromkeys(punc_list, " "))
new_s = s.lower().translate(t)

Answer 4

适用于 Python 3.8.2

import string 

punc_list = '.;:!?/\,#@$&)(\'"'
replacement =  ' '*len(punc_list)

def func(s):
    new_s = s.translate(str.maketrans(punc_list, replacement))
    return new_s

print(func("Hey! M'y nam;e i's"))

Answer 5

if i not in punc_list: ，我只需添加一个 else 语句，以便代码如下所示：

punc_list = [".",";",":","!","?","/","\\",",","#","@","$","&",")","(","'","\""]
new_s = ''
for i in s:
    if i not in punc_list:
        new_s += i
    else:
        new_s += ' '

return new_s.lower()

所有这些都是说：如果该字符不在标点符号列表中，则将其添加到新string 。 如果它在标点符号列表中，则为新string添加一个空格。

Answer 6

就像@DYZ 所说的，你只需要另一个用空格替换特殊字符的条件语句：

def func(s):
    punc_list = [".",";",":","!","?","/","\\",",","#","@","$","&",")","(","'","\""]
    new_s = ''
    for i in s:
        if i not in punc_list:
            new_s += i
        else:
            new_s += ' '
    return new_s.lower()

s = ("Hey! M'y nam;e i's")
new_s = func(s)
print (new_s)

输出看起来像你想要的： hey my nam eis

Answer 7

请参阅此代码，使用 2 个循环：

punc_list = [".",";",":","!","?","/","\\",",","#","@","$","&",")","(","'","\""]
s = "Hey! M'y nam;e i's"
new_s = ''

for x in punc_list:
  for i in s:
    if i==x:
        s=s.replace(i,new_s)


print(s)