#Import the cmath module
import cmath

print(cmath.phase( 3 + 5j))

The cmath.phase() function returns the phase of a complex number which is the angle between the real axis and the vector representing the number.

The return value is in radians and is between and π, inclusive.

cmath.phase(x)
x  The value(real or complex) whose phase is to be determined. If the value is a real number, it is first converted into a complex value before the operation.

This function returns a float representing the phase of the complex number, x, in radians.

import cmath

print(cmath.phase(2))
print(cmath.phase(-3 + 4j))
print(cmath.phase(2 + 5j))
print(cmath.phase(10 - 7j))
print(cmath.phase(complex(5, 5)))
print(cmath.phase(cmath.inf))