Create a numpy array when indexes of (fixed) elements are given

Question

I have a numpy array of indexes e.g. [1,3,12]. I want to create another array from this such that at these indexes, I get a non-zero elements e.g. 1. So in this case, with input [1,3,12], I should get [0,1,0,1,0,0,0,0,0,0,0,0,1]. I can do it in a for loop, is there a short numpy function to achieve this?

Daniel · Accepted Answer · 2015-12-25 08:21:14Z

1

With numpy you can index with lists directly:

a = [1,3,12]
vector = numpy.zeros(shape=max(a) + 1)
vector[a] = 1

edited Dec 25, 2015 at 8:21

answered Dec 25, 2015 at 7:58

Daniel

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1 Comment

Dilawar Over a year ago

Great. Thanks. It worked after tiny change shape = max(a) + 1.

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