python - Removing every other element in NumPy -


i can't life of me figure out.

i'm trying remove every other element in second axis of array. did in matlab arr(:,:,2:2:end) = [];, when tried same in python , compare 2 outputs, different matrix.

i've tried arr = np.delete(arr,np.arange(0,arr.shape[2],2),2) , arr = arr[:,:,1::2], neither seem come matlab.


example:

matlab

    disp(['before: ',str(arr[21,32,11])])     arr(:,:,2:2:end) = [];     disp(['after: ',str(arr[21,32,11])])

output:

    before: 99089     after: 65699


python

    print 'before: ' + str(arr[20,31,10])     arr = arr[:,:,1::2] # same output np.delete(arr,np.arange(0,arr.shape[2],2),2)      print 'after: ' + str(arr[20,31,10])

output:

    before: 99089     after: 62360

i hope i'm not overlooking fundamental.

you trying delete every other element starting second element onwards in last axis. in other words, trying keep every other element starting first element onwards in axis.

thus, working other way around of selecting elements instead of deleting elements, matlab code arr(:,:,2:2:end) = [] equivalent (neglecting performance numbers) :

arr = arr(:,:,1:2:end)

in python/numpy, be:

arr = arr[:,:,0::2]

or simply:

arr = arr[:,:,::2]

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