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问题：查找字符串中子字符串的最后一次出现，将其替换
回答 0
回答 1
回答 2
回答 3
回答 4
回答 5
回答 6

问题：查找字符串中子字符串的最后一次出现，将其替换

因此，我有一长串具有相同格式的字符串，并且我想找到最后一个“”。每个字符，然后将其替换为“。-”。我尝试使用rfind，但似乎无法正确利用它来执行此操作。

点击查看英文原文

So I have a long list of strings in the same format, and I want to find the last “.” character in each one, and replace it with “. – “. I’ve tried using rfind, but I can’t seem to utilize it properly to do this.

回答 0

这应该做

old_string = "this is going to have a full stop. some written sstuff!"
k = old_string.rfind(".")
new_string = old_string[:k] + ". - " + old_string[k+1:]
点击查看英文原文

This should do it

old_string = "this is going to have a full stop. some written sstuff!"
k = old_string.rfind(".")
new_string = old_string[:k] + ". - " + old_string[k+1:]

回答 1

要从右侧替换：

def replace_right(source, target, replacement, replacements=None):
    return replacement.join(source.rsplit(target, replacements))

正在使用：

>>> replace_right("asd.asd.asd.", ".", ". -", 1)
'asd.asd.asd. -'
点击查看英文原文

To replace from the right:

def replace_right(source, target, replacement, replacements=None):
    return replacement.join(source.rsplit(target, replacements))

In use:

>>> replace_right("asd.asd.asd.", ".", ". -", 1)
'asd.asd.asd. -'

回答 2

我会使用正则表达式：

import re
new_list = [re.sub(r"\.(?=[^.]*$)", r". - ", s) for s in old_list]
点击查看英文原文

I would use a regex:

import re
new_list = [re.sub(r"\.(?=[^.]*$)", r". - ", s) for s in old_list]

回答 3

一行代码是：

str=str[::-1].replace(".",".-",1)[::-1]

点击查看英文原文

A one liner would be :

str=str[::-1].replace(".",".-",1)[::-1]

回答 4

您可以使用下面的函数来代替从右至右的单词的第一个出现。

def replace_from_right(text: str, original_text: str, new_text: str) -> str:
    """ Replace first occurrence of original_text by new_text. """
    return text[::-1].replace(original_text[::-1], new_text[::-1], 1)[::-1]
点击查看英文原文

You can use the function below which replaces the first occurrence of the word from right.

def replace_from_right(text: str, original_text: str, new_text: str) -> str:
    """ Replace first occurrence of original_text by new_text. """
    return text[::-1].replace(original_text[::-1], new_text[::-1], 1)[::-1]

回答 5

a = "A long string with a . in the middle ending with ."

＃如果要查找任何字符串的最后一次出现的索引，在我们的示例中，我们＃将查找with的最后一次出现的索引

index = a.rfind("with")

＃结果将是44，因为索引从0开始。

点击查看英文原文 
a = "A long string with a . in the middle ending with ."

# if you want to find the index of the last occurrence of any string, In our case we #will find the index of the last occurrence of with

index = a.rfind("with")

# the result will be 44, as index starts from 0.

回答 6

天真的方法：

a = "A long string with a . in the middle ending with ."
fchar = '.'
rchar = '. -'
a[::-1].replace(fchar, rchar[::-1], 1)[::-1]

Out[2]: 'A long string with a . in the middle ending with . -'

Aditya Sihag的回答只有一个rfind：

pos = a.rfind('.')
a[:pos] + '. -' + a[pos+1:]
点击查看英文原文

Naïve approach:

a = "A long string with a . in the middle ending with ."
fchar = '.'
rchar = '. -'
a[::-1].replace(fchar, rchar[::-1], 1)[::-1]

Out[2]: 'A long string with a . in the middle ending with . -'

Aditya Sihag’s answer with a single rfind:

pos = a.rfind('.')
a[:pos] + '. -' + a[pos+1:]
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