numpy.delete method to delete columns

This time I will bring you numpy.deleteHow to delete a column, what are the precautions for numpy.delete to delete a column, the following is a practical case, let's take a look.

Basic introduction:

numpy.delete
numpy.delete(arr, obj, axis=None)[source]
 Return a new array with sub-arrays along an axis deleted. For a one dimensional array, this returns those entries not returned by arr[obj].
 Parameters:	
 arr : array_like
  Input array.
 obj : slice, int or array of ints
  Indicate which sub-arrays to remove.
 axis : int, optional
  The axis along which to delete the subarray defined by obj. If axis is None, obj is applied to the flattened array.
 Returns:	
 out : ndarray
  A copy of arr with the elements specified by obj removed. Note that delete does not occur in-place. If axis is None, out is a flattened array.

Example:

1. Delete one column

>>> dataset=[[1,2,3],[2,3,4],[4,5,6]] 
>>> import numpy as np 
>>> dataset = np.delete(dataset, -1, axis=1) 
>>> dataset 
array([[1, 2], 
  [2, 3], 
  [4, 5]])

2. Delete multiple columns

arr = np.array([[1,2,3,4], [5,6,7,8], [9,10,11,12]]) 
np.delete(arr, [1,2], axis=1) 
array([[ 1, 4], 
  [ 5, 8], 
  [ 9, 12]])

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