drop a column in numpy ndarray

Question

I've try delete numpy ndarray's 1st column (eg. A, B, C ... A, B ) through

x = np.delete(x, 0, axis=1)

or

x = np.delete(x, 0, axis=0)

However, it's not work.

ndarray shape = ( 30000, 120, 15) 

[[['A' 0.0 0.0 ..., 0.0 0.0 'Y']
  ['B' 0.0 0.0 ..., 0.0 0.0 'Y']
  ['C' 0.0 0.0 ..., 0.0 0.0 'N']
   ..., 
  ['A' 0.0 0.0 ..., 0.0 0.0 'Y']
  ['B' 41.0 0.0 ..., 0.0 0.0 'N']]]

How do I resolve this... Thank you.

Note that you can access the data as : x[:,:,1:] to have column 1 to end from you array. — Vuwox
– Vuwox, Commented Jun 1, 2017 at 2:32

akuiper · Accepted Answer · 2017-06-01 02:30:17Z

3

The column is the 3rd dimension of the array, you need axis = 2:

import numpy as np
x = np.array([[['A', 1, 2],
              ['B', 2, 3]],
             [['A', 1, 2],
              ['B', 2, 3]]])

x.shape
#(2, 2, 3)

np.delete(x, 0, axis=2)
#array([[['1', '2'],
#        ['2', '3']],
# 
#       [['1', '2'],
#        ['2', '3']]], 
#      dtype='<U1')

Or you can use the slicing index:

x[...,1:]

#array([[['1', '2'],
#        ['2', '3']],
# 
#        [['1', '2'],
#         ['2', '3']]], 
#       dtype='<U1')

answered Jun 1, 2017 at 2:30

akuiper

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1 Comment

Chris Joo Over a year ago

Thank you sooooooooooooo much!

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