python 除去字符串开头结尾字母、数字

import string
a = 'XQX大家好'

print a.strip(string.uppercase)

>>> import string

>>> string.uppercase

'ABCDEFGHIJKLMNOPQRSTUVWXYZ'

>>> string.lowercase

'abcdefghijklmnopqrstuvwxyz'

>>> string.letters

'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'

>>> string.digits

'0123456789'