删除python中字符串中不是字母的第一个字符后面的任何内容

Question

关于使用正则表达式从字符串中剥离非字母数字字符有几个问题.我想要做的是删除第一个不是字母或单个空格的字符(包括数字和双空格)后的每个字符,包括字母.

例如:

My string is #not very beautiful 

应该成为

My string is

要么

Are you 9 years old?

应该成为

Are you

和

this is the last  example

应该成为

this is the last

我该如何做到这一点？

Answer 1

如何split开始[^A-Za-z ]|并采取第一个元素？您可以稍后修剪可能的空白区域:

import re
re.split("[^A-Za-z ]|  ", "My string is #not very beautiful")[0].strip()
# 'My string is'

re.split("[^A-Za-z ]|  ", "this is the last  example")[0].strip()
# 'this is the last'

re.split("[^A-Za-z ]|  ", "Are you 9 years old?")[0].strip()
# 'Are you'

[^A-Za-z ]|包含两种模式,第一种模式是单个字符,既不是字母也不是空格; 第二种模式是双白空间; 拆分这两种模式中的一种,拆分后的第一个元素应该是您正在寻找的.

Answer 2

创建一个白名单，并在看到不在该白名单中的内容时停止：

import itertools
import string

def rstrip(s, whitelist=None):
    if whitelist is None:
        whitelist = set(string.ascii_letters + ' ')  # set the whitelist to a default of all letters A-Z and a-z and a space
    # split on double-whitespace and take the first split (this will work even if there's no double-whitespace in the string)
    # use `itertools.takewhile` to include the characters that in the whitelist
    # use `join` to join them inot one single string

    return ''.join(itertools.takewhile(whitelist.__contains__, s.split('  ', 1)[0]))