Finding the exponent of n = 2**x using bitwise operations [logarithm in base 2 of n]

Question

Is there a straightforward way to extracting the exponent from a power of 2 using bitwise operations only?

EDIT: Although the question was originall

Answer 1

Late to the party, but how about int.bit_length(n) - 1? You asked for straightforward, and that seems the simplest to me. The CPython implementation looks reasonably performant.

• Reference documentation
• CPython source code