# Python | Multiply 2d numpy array corresponding to 1d array

• Last Updated : 15 Mar, 2019

Given a two numpy arrays, the task is to multiply 2d numpy array with 1d numpy array each row corresponding to one element in numpy. Let’s discuss a few methods for a given task.

Method #1: Using np.newaxis()

 `# Python code to demonstrate``# multiplication of 2d array``# with 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]`` ` `# printing result``print``(``"New resulting array: "``, result)`

Output:

```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 axis as none

 `# Python code to demonstrate``# multiplication of 2d array``# with 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``]`` ` `# printing result``print``(``"New resulting array: "``, result)`

Output:

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

Method #3: Using transpose()

 `# python code to demonstrate``# multiplication of 2d array``# with 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`` ` `# printing result``print``(``"New resulting array: "``, result)`

Output:

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

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