问题
Similarly (-1==-1 & 1==1) is also False.
Apologies if this is something obvious but I can't find an explanation for it.
回答1:
& is the bitwise AND operator. As mentioned in the documentation, Bitwise operators have higher precedence than logical operators, so
0 == 0 & 1 == 1
Becomes
0 == (0 & 1) == 1
And you can imagine it goes downhill from there:
0 == (0 & 1) == 1
=> 0 == 0 == 1
=> 0 == 0 and 0 == 1
=> True and False
=> False
Assuming what you wanted was a logical AND, the python way to do that would be using and:
0 == 0 and 1 == 1
Which gives you True as you'd expect.
回答2:
Lets break this up.
The highest priority sign here is the brackets. Except we're wrapping the entire expression, so they don't do anything.
Next we have the bitwise operator &.
0 & 1 which equals 0.
This leaves us with 0 == 0 == 1
As 0 does not equal 1, we get False.
For reference, here is the python documentation about operator precedence.
来源：https://stackoverflow.com/questions/46782825/why-is-the-expression-0-0-1-1-evaluating-to-false