Python | Multiply a two-dimensional array corresponding to a 1d array

Arrays | NumPy | Python Methods and Functions

Method # 1: Using np.newaxis ()

# Python code for demonstration
# multiplying a 2d array
# with a 1d array

import numpy as np

ini_array1 = np.array ([[ 1 , 2 , 3 ], [ 2 , 4 , 5 ], [ 1 , 2 , 3 ]])

ini_array2 = np.array ([ 0 , 2 , 3 ])

# printing initial arrays

print ( "initial array" , str (ini_array1))

# Multiplying arrays

result = ini_array1 * ini_array2 [:, np.newaxis]

# print result

print ( " New resulting array: " , result)

Exit:

 initial array [[1 2 3] [2 4 5] [1 2 3]] New resulting array: [[0 0 0] [4 8 10 ] [3 6 9]]

Method # 2: Using the Axis As Not

# Python code for demonstration
# multiplying a 2d array
# with a 1d array

import numpy as np

   
   ini_array1   =   np.array ([[  1  ,   2  ,   3  ], [  2  ,   4  ,   5  ], [  1  ,   2  ,   3  ]]) 
   ini_array2   =   np.array ([  0  ,   2  ,   3   ]) 
   
  # printing initial arrays  
   print   (  "initial array"  ,   str   (ini_array1)) 
   
  # Multiplying arrays  
   result   =   ini_array1   *   ini_array2 [:,   None  ] 
   
  # print result  
   print   (  "New resulting array:"  , result)

Exit:

 initial array [[1 2 3] [2 4 5] [1 2 3]] New resulting array: [[0 0 0] [4 8 10] [3 6 9]]

Spo ex # 3: Using transpose ()

# Python code for demonstration
# multiplying a 2d array
# with a 1d array

import numpy as np

ini_array1 = np.array ([ [ 1 , 2 , 3 ], [ 2 , 4 , 5 ], [ 1 , 2 , 3 ]])

ini_array2 = np.array ([ 0 , 2 , 3 ])

# printing initial arrays

print ( "initial array" , str (ini_array1))

# Multiplying arrays

result = (ini_array1.T * ini_array2) .T

# print result

print ( "New resulting array:" , result)

Exit:

 initial array [[1 2 3] [2 4 5] [1 2 3]] New resulting array: [[0 0 0] [4 8 10] [3 6 9] ]

Python | Multiply a two-dimensional array corresponding to a 1d array

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