Python：只保留字符串中的字母
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Python: keep only letters in string
提问by
What is the best way to remove all characters from a string that are not in the alphabet? I mean, remove all spaces, interpunction, brackets, numbers, mathematical operators..
从字符串中删除不在字母表中的所有字符的最佳方法是什么？我的意思是，删除所有空格、标点符号、括号、数字、数学运算符..
For example:
例如：
input: 'as32{ vd"s k!+'
output: 'asvdsk'
回答by timgeb
You could use re, but you don't really need to.
你可以使用re，但你真的不需要。
>>> s = 'as32{ vd"s k!+'
>>> ''.join(x for x in s if x.isalpha())
'asvdsk'
>>> filter(str.isalpha, s) # works in python-2.7
'asvdsk'
>>> ''.join(filter(str.isalpha, s)) # works in python3
'asvdsk'
回答by nehem
If you want to use regular expression, This should be quicker
如果你想使用正则表达式，这应该更快
import re
s = 'as32{ vd"s k!+'
print re.sub('[^a-zA-Z]+', '', s)
prints
'asvdsk'
印刷
'asvdsk'
回答by Patrick Yu
Here is a method that uses ASCII ranges to check whether an character is in the upper/lower case alphabet (and appends it to a string if it is):
这是一种使用 ASCII 范围检查字符是否在大写/小写字母表中的方法（如果是，则将其附加到字符串中）：
s = 'as32{ vd"s k!+'
sfiltered = ''
for char in s:
if((ord(char) >= 97 and ord(char) <= 122) or (ord(char) >= 65 and ord(char) <= 90)):
sfiltered += char
The variable sfilteredwill show the result, which is 'asvdsk'as expected.
该变量sfiltered将显示结果，'asvdsk'正如预期的那样。
