问题
I came across with the code syntax d //= 2 where d is a variable. This is not a part of any loop, I don't quite get the expression.
Can anybody enlighten me please?
回答1:
// is a floor division operator. The = beside it means to operate on the variable "in-place". It's similar to the += and *= operators, if you've seen those before, except for this is with division.
Suppose I have a variable called d. I set it's value to 65, like this.
>>> d = 65
Calling d //= 2 will divide d by 2, and then assign that result to d. Since, d // 2 is 32 (32.5, but with the decimal part taken off), d becomes 32:
>>> d //= 2
>>> d
32
It's the same as calling d = d // 2.
回答2:
It divides d by 2, rounding down. Python can be run interactively, Try it.
$ python
Python 2.7.10 (default, Oct 23 2015, 19:19:21)
>>> a = 4
>>> a //= 2
>>> a
2
回答3:
Divides the variable with floor division by two and assigns the new amount to the variable.
来源：https://stackoverflow.com/questions/40274205/what-does-the-variable-a-value-syntax-mean-in-python