'complex' function with string argument.

[wxjmfauth at gmail.com]

z = a + b*i     with a, b, elements of R
z = r*exp(i*phi)    with r, phi, elements of R
z = [[a, -b], [b, a]]   with a, b, elements of R

This is, in my mind, more questionable:

>>> complex(2, 1+1j)
(1+1j)
>>> 
>>> print(complex.__doc__)
complex(real[, imag]) -> complex number

Create a complex number from a real part and an optional imaginary part.
This is equivalent to (real + imag*1j) where imag defaults to 0.

jmf