'Power of' in python

Question

Why is it when:

>> b = -1 

>> b**2 

1

But:

>> -1**2 

-1

If i import the math library, it's no problem.

>> from math import pow 

>> pow(b,2) 

1.0 

>> pow(-1,2) 

1.0

Answer 1

The power operator binds more tightly than unary operators on its left; it binds less tightly than unary operators on its right.

Thus, in an unparenthesized sequence of power and unary operators, the operators are evaluated from right to left (this does not constrain the evaluation order for the operands): -1**2 results in -1.

To know more about this you can have a look at the following video tutorial:-