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。
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:]
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. -'
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"\.(?=[^.]*$)", r". - ", s) for s in old_list]
I would use a regex:
import re
new_list = [re.sub(r"\.(?=[^.]*$)", r". - ", s) for s in old_list]
回答 3
一行代码是：
str=str[::-1].replace(".",".-",1)[::-1]
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]
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。
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:]
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:]
