string模块

string.ascii_letters  # 返回小写字母大写字母字符串
# 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'

string.ascii_uppercase # 返回大写字母的字符串
# 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'

string.ascii_lowercase # 返回小写字母的字符串
# 'abcdefghijklmnopqrstuvwxyz'

string.punctuation # 打印特殊字符
# '!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~'

string.digits  # 打印数字
# '0123456789'