Given a numpy array, write a programme to delete columns from numpy array. Examples –
Input: [['akshat', 'nikhil'], ['manjeeet', 'akash']] Output: [['akshat']['manjeeet']] Input: [[1, 0, 0, 1, 0], [0, 1, 2, 1, 1]] Output: [[1 0 1 0][0 2 1 1]]
Given below are various methods to delete columns from numpy array. Method #1: Using np.delete()
Python3
# Python code to demonstrate# deletion of columns from numpy arrayimport numpy as np# initialising numpy arrayini_array = np.array([[1, 0, 0, 1, 0], [0, 1, 2, 1, 1]]) # deleting second column from arrayresult = np.delete(ini_array, 1, 1)# print resultprint ("Resultant Array :"+str(result)) |
Output:
Resultant Array :[[1 0 1 0] [0 2 1 1]]
Time Complexity: O(n)
Space Complexity: O(n)
where n is length of array
Method #2: Using compress() and logical_not()
Python3
# Python code to demonstrate# deletion of columns from numpy arrayimport numpy as np# initialising numpy arrayini_array = np.array([[1, 0, 0, 1, 0], [1, 2, 0, 0, 1]])z = [False, True, False, False, False] # deleting second column from arrayresult = ini_array.compress(np.logical_not(z), axis = 1)# print resultprint ("Resultant Array :"+str(result)) |
Output:
Resultant Array :[[1 0 1 0] [1 0 0 1]]
Time Complexity: O(n)
Space Complexity: O(n)
where n is length of array
Method #3: Using logical_not()
Python3
# Python code to demonstrate# deletion of columns from numpy arrayimport numpy as np# initialising numpy arrayini_array = np.array([[1, 0, 0, 1, 0], [1, 2, 0, 0, 1]])z = [False, True, False, False, False] # deleting second column from arrayresult = ini_array[:, np.logical_not(z)]# print resultprint ("Resultant Array :"+str(result)) |
Output:
Resultant Array :[[1 0 1 0] [1 0 0 1]]
Time Complexity: O(n)
Space Complexity: O(n)
where n is length of array
