python运算子=-是做什么的？

Question

What does the python operator =- do? I'm not asking about the -= operator, which I realize is shorthand for x = x - value .

Answer 1

Actually, the operator =- does not exist. It is only = (- value) . So the negative of the value.

Example:

>>> x =- 1
>>> x
-1

Answer 2

Why not test it?

In [11]: x = 1

In [12]: y = 2

In [13]: y=-x

In [14]: y
Out[14]: -1

As you can see it does nothing, but sets a negative value of the variable on the right hand side

Answer 3

There is no =- operator. Depending on the context this might be two operators, eg x =- y is equivalent to x = (-y) (so there are two operators: assignment and negation) or an assignment with a negative constant: x =- 1 is equivalent to x = (-1) (in this context - is not an operator, it's just a negative constant).