Numpy: Creating a complex array from 2 real ones?

Question

I want to combine 2 parts of the same array to make a complex array:

Data[:,:,:,0] , Data[:,:,:,1] 

These don't work:

x = np.complex(Data[:,:,:,0], Data[:,:,:,1]) x = complex(Data[:,:,:,0], Data[:,:,:,1]) 

Am I missing something? Does numpy not like performing array functions on complex numbers? Here's the error:

TypeError: only length-1 arrays can be converted to Python scalars 

Answer 1

This seems to do what you want:

numpy.apply_along_axis(lambda args: [complex(*args)], 3, Data) 

Here is another solution:

# The ellipsis is equivalent here to ":,:,:"... numpy.vectorize(complex)(Data[...,0], Data[...,1]) 

And yet another simpler solution:

Data[...,0] + 1j * Data[...,1] 

PS: If you want to save memory (no intermediate array):

result = 1j*Data[...,1]; result += Data[...,0] 

devS' solution below is also fast.