如何检查字符串是否仅包含字母数字字符和短划线？

Question

The string I'm testing can be matched with [\\w-]+ . Can I test if a string conforms to this in Python, instead of having a list of the disallowed characters and testing for that?

Answer 1

If you want to test a string against a regular expression, use the re library

import re
valid = re.match('^[\w-]+$', str) is not None

Answer 2

Python has regex as well:

import re
if re.match('^[\w-]+$', s):
    ...

Or you could create a list of allowed characters:

from string import ascii_letters
if all(c in ascii_letters+'-' for c in s):
    ...

Answer 3

Without importing any module just using pure python, remove any none alpha, numeric except dashes.

string = '#Remove-*crap?-from-this-STRING-123$%'

filter_char = lambda char: char.isalnum() or char == '-'
filter(filter_char, string)

# This returns--> 'Remove-crap-from-this-STRING-123'

Or in one line:

''.join([c for c in string if c.isalnum() or c in ['-']])

Answer 4

To test if the string contains only alphanumeric and dashes, I would use

import re
found_s = re.findall('^[\w-]+$', s)
valid = bool(found_s) and found_s[0] == s