Python 如何检查字符串中的特殊字符？
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How to check a string for a special character?
提问by Chuvi
I can only use a string in my program if it contains no special characters except underscore _. How can I check this?
我只能在我的程序中使用一个字符串，如果它不包含除下划线之外的特殊字符_。我该如何检查？
I tried using unicodedata library. But the special characters just got replaced by standard characters.
我尝试使用 unicodedata 库。但是特殊字符刚刚被标准字符取代。
采纳答案by thefourtheye
You can use string.punctuationand anyfunction like this
您可以像这样使用string.punctuation和any运行
import string
invalidChars = set(string.punctuation.replace("_", ""))
if any(char in invalidChars for char in word):
print "Invalid"
else:
print "Valid"
With this line
有了这条线
invalidChars = set(string.punctuation.replace("_", ""))
we are preparing a list of punctuation characters which are not allowed. As you want _to be allowed, we are removing _from the list and preparing new set as invalidChars. Because lookups are faster in sets.
我们正在准备一个不允许使用的标点符号列表。由于您希望_被允许，我们正在_从列表中删除并准备新的集合为invalidChars。因为在集合中查找速度更快。
anyfunction will return Trueif atleast one of the characters is in invalidChars.
anyTrue如果至少有一个字符在中，则函数将返回invalidChars。
Edit:As asked in the comments, this is the regular expression solution. Regular expression taken from https://stackoverflow.com/a/336220/1903116
编辑：正如评论中所问，这是正则表达式解决方案。取自https://stackoverflow.com/a/336220/1903116 的正则表达式
word = "Welcome"
import re
print "Valid" if re.match("^[a-zA-Z0-9_]*$", word) else "Invalid"
回答by U2EF1
You will need to define "special characters", but it's likely that for some string syou mean:
您将需要定义“特殊字符”，但对于某些字符串，s您的意思很可能是：
import re
if re.match(r'^\w+$', s):
# s is good-to-go
