Using pandas one can do:
A = np.array([2,0,1,4]) B = np.array([1,2,0]) s = pd.Series(range(len(B)), index=B) s[A].values array([ 1., 2., 0., nan])
On Wed, Dec 30, 2015 at 8:45 AM, Nicolas P. Rougier < Nicolas.Rougier@inria.fr> wrote:
I’m scratching my head around a small problem but I can’t find a vectorized solution. I have 2 arrays A and B and I would like to get the indices (relative to B) of elements of A that are in B:
A = np.array([2,0,1,4]) B = np.array([1,2,0]) print (some_function(A,B)) [1,2,0]
# A[0] == 2 is in B and 2 == B[1] -> 1 # A[1] == 0 is in B and 0 == B[2] -> 2 # A[2] == 1 is in B and 1 == B[0] -> 0
Any idea ? I tried numpy.in1d with no luck.
Nicolas
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