Question

How can I select multiple elements from a python array? I know that this is possible in numpy array but I cannot use numpy array in this case. I want to select certain elements of an array similar to masked array usage but i get following error in python

 nonzero = numpyarray.nonzero()
 pythonarray[nonzero] = numpyarray[nonzero]
 *** TypeError: only integer arrays with one element can be converted to an index

numpyarray[nonzero] works fine but I cannot access pythonarray[nonzero]. Is there a way to do this in python array?

Answer 1

Just use a loop:

for idx in nonzero:
    pythonarray[idx] = numpyarray[idx]

Numpy arrays probably support n-ary indices to maximize performance; Python lists don’t go that far with optimisations so you have to use the simpler approach.