删除特定字符集后的所有字符

Question

s = 'These are the characters, from this point I want to delete everything'

当Python看到来自＆＃39;时，我想删除之后的所有内容。

Answer 1

我会使用index。

def shorten(s, subs):
    i = s.index(subs)
    return s[:i+len(subs)]

用法：

s = 'These are the characters, from this point I want to delete everything'
print(shorten(s, 'from'))

输出：

  

这些是来自

的字符

Answer 2

您可以使用takewhile拆分和重新加入字符串，以消费直至来自的字词：

s = 'These are the characters, from this point I want to delete everything'

from itertools import takewhile

new_s = " ".join(takewhile(lambda x: x != "from", s.split(" ")))

你也可以分开＆＃34;来自＆＃34;曾经和以前的角色：

s = 'These are the characters, from this point I want to delete everything'

new_s = s.split("from",1 )[0]

但是，这将分散于＆＃34;来自＆＃34;无论是实际的单词还是子串，可能都不是你想要的。

如果你想要一个完全匹配并处理各种不同的可能性，比如from和preiod之间没有空格，逗号等......你需要使用word boundary-的正则表达式：

import  re
new_s = re.split(r"\bfrom\b",s, 1)[0]