Getting each column in a 3d numpy array

Question

I converted an image from RBG to CieLab, now I need to use the value of the cielab to calculate some equations. I have been trying to get the value of each column in the array. For example if I have:

List =

   [[[ 65 234 169]
     [203 191 245]
     [ 36  58 196]
     [207 208 143]
     [251 208 187]]

    [[ 79  69 237]
     [ 13 124  42]
     [104 165  82]
     [170 178 178]
     [ 66  42 210]]

   [[ 40 163 219]
    [142  37 140]
    [ 75 205 143]
    [246  30 221]
    [ 16  98 102]]]

How can I get it to give me the values of each columns like:

1st_column =

Thank you.

Assuming `a` the array, use `a[...,0]` – mozway Jun 01 '22 at 21:02 — mozway, Jun 01 '22 at 21:02
@mozway. I didn't know about ellipsis!!! Great – Corralien Jun 01 '22 at 21:03 — Corralien, Jun 01 '22 at 21:03
Just add it to your answer if you want – mozway Jun 01 '22 at 21:04 — mozway, Jun 01 '22 at 21:04

Corralien · Accepted Answer · 2022-06-01T21:30:45.317

1

Try:

>>> m[:, :, 0]
array([[ 65, 203,  36, 207, 251],
       [ 79,  13, 104, 170,  66],
       [ 40, 142,  75, 246,  16]])

As suggested by @mozway, you can use the ellipsis syntax: m[..., 0].

To know more, read How do you use the ellipsis slicing syntax in Python?

You can also flatten your array:

>>> m[:, :, 0].flatten()
array([ 65, 203,  36, 207, 251,  79,  13, 104, 170,  66,  40, 142,  75, 246,  16])

edited Jun 01 '22 at 21:30

answered Jun 01 '22 at 21:02

Corralien

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Getting each column in a 3d numpy array

1 Answers1