I'm newbie in python. I have a three variables x, y, z as a int. I have comparison three variables in if condition. I'm confused about following code result.
The expression x < y <= z evaluates to false.
Let's assume x = 10, y = 5 and z = 0. if x < y become False, then False <= 0 become True. but output is False. Why?
My python script:
#!/usr/bin/python
x = 10
y = 5
z = 0
if (x < y < z):
print"True"
else:
print"False"
The document say:
Comparisons can be chained arbitrarily; for example, x < y <= z is equivalent to x < y and y <= z, except that y is evaluated only once (but in both cases z is not evaluated at all when x < y is found to be false).
x < y <= z neither means (x < y) <= z nor x < (y <= z). x < y <= z is equivalent to x < y and y <= z, and is evaluates from left-to-right.
Logical AND do not have associativity in Python unlike C and C++. There are separate rules for sequences of this kind of operator and cannot be expressed as associativity.
x < y and y <= z only evaluates the second argument if the first one is true because and is a short-circuit operator.
That expression is evaluated as:
if (x < y and y < z):
pass
So now you see why it is false is because x is not less than y
