点符号字符串操作 [英] Dot notation string manipulation

问题描述

有没有办法使用以下方式在 Python 中操作字符串?

Is there a way to manipulate a string in Python using the following ways?

对于任何以点表示法存储的字符串，例如:

For any string that is stored in dot notation, for example:

s = "classes.students.grades"

有没有办法将字符串更改为以下内容:

Is there a way to change the string to the following:

"classes.students"

基本上，删除包括上一期在内的所有内容.所以 "restaurants.spanish.food.salty" 会变成 "restaurants.spanish.food".

Basically, remove everything up to and including the last period. So "restaurants.spanish.food.salty" would become "restaurants.spanish.food".

另外，有什么方法可以确定最后一个时期之后发生了什么?我想这样做的原因是我想使用 isDigit().

Additionally, is there any way to identify what comes after the last period? The reason I want to do this is I want to use isDigit().

所以，如果是 classes.students.grades.0 我可以以某种方式获取 0，所以我可以使用带有 isdigit，然后说如果最后一个句点之后的字符串部分(在这种情况下为 0)是一个数字，则将其删除，否则，保留它.

So, if it was classes.students.grades.0 could I grab the 0 somehow, so I could use an if statement with isdigit, and say if the part of the string after the last period (so 0 in this case) is a digit, remove it, otherwise, leave it.

推荐答案

你可以使用 split 和 <代码>加入:

s = "classes.students.grades"
print '.'.join(s.split('.')[:-1])

您在 上拆分字符串. - 它会给您一个字符串列表，之后您将列表元素连接回用 分隔它们的字符串.

You are splitting the string on . - it'll give you a list of strings, after that you are joining the list elements back to string separating them by .

[:-1] 将选择列表中的所有元素，但最后一个

[:-1] will pick all the elements from the list but the last one

检查最后一个之后的内容.:

s.split('.')[-1]

另一种方法是使用 rsplit.它的工作方式与 split 相同，但如果您提供 ma​​xsplit 参数，它将从末尾开始拆分字符串:

Another way is to use rsplit. It works the same way as split but if you provide maxsplit parameter it'll split the string starting from the end:

rest, last = s.rsplit('.', 1)

'classes.students'
'grades'

您也可以使用re.sub 用空字符串替换最后一个 . 之后的部分:

You can also use re.sub to substitute the part after the last . with an empty string:

re.sub('\.[^.]+$', '', s)

你的问题的最后一部分是用 [] 换行，我建议使用 format 和 列表理解:

And the last part of your question to wrap words in [] i would recommend to use format and list comprehension:

''.join("[{}]".format(e) for e in s.split('.'))

它会给你想要的输出:

[classes][students][grades]

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