问题
I come from a c style languages, so I am natural in using != as not equal, but when I came to Python, from the documentation I read, I learned that for this purpose the <> operator is used.
Recently, I have seen a lot of code using !=, so my question is if one of them is preferred over the other or is one of them deprecated.
Also, I would like to know if there is any difference between them.
回答1:
Python 2 supports both, in python 3 the <> operator has been removed.
There is no difference between the two, but != is the preferred form.
回答2:
From the official docs you linked
!= can also be written <>, but this is an obsolete usage kept for backwards compatibility only. New code should always use !=.
I believe the rationale for originally accepting <> was that it looked more natural for someone coming from a mathematical background than the common C-style != operator.
回答3:
I don't know what documentation you read, but I'm not aware of any that recommends <> over !=. PEP8, the main style guide, doesn't mention any such recommendation.
回答4:
Just for the record,<> has been obsolete since at least as early as version 1.4, which was released in October 1996.
来源：https://stackoverflow.com/questions/12351221/python-not-equal-operator