# How to Multiply NumPy array | np.Multiply

In this post, we are going to learn about how to Multiply NumPy array. We are going to learn this with the help of many examples. To run all the below programs the Numpy library must be installed on the system and if the numpy library is installed on our system we can import it into our program. By the end of this post, you will be able to answer the below questions.

• NumPy Program to Multiply 2 Scaler numbers
• NumPy Program to linear or 1-D Numpy Array
• NumPy Program to two Multiply multi-dimensional Array
• How to do element wise multiplication in numpy.

### Numpy Multiply() function

In the python Numpy library, we have multiply() function that is used to do the element-wise multiplication of two arrays.

#### Syntax

```numpy.multiply(arr1, arr2, /, out=None, *, where=True, casting='same_kind', order='K', dtype=None, subok=True[, signature, extobj]) = <ufunc 'multiply'>
```

### 1. NumPy Program to Multiply 2 Scaler numbers

In this python program, we are using the np.multiply() function to multiply two scalar numbers by simply passing the scalar numbers as an argument to np.multiply() function.

```import numpy as np
num1 = 5
num2 = 4

product = np.multiply(num1, num2)
print ("Multiplication Result is : ", product)

```

Output

```Multiplication Result is : 20
```

### 2. NumPy Program to linear 1D Numpy Array

In this python program, we have used np.multiply() function to multiply two 1D numpy arrays by simply passing the arrays as arguments to np.multiply() function. This is how to multiply two linear arrays using np. multiply() function.

```import numpy as np
arr1 = np.array([1, 2, 3, 4, 5] )
arr2 = np.array([5, 4, 3, 2, 1] )

print ("1st Input array : ", arr1)
print ("2nd Input array : ", arr2)

product = np.multiply(arr1, arr2)
print ("Multiplication Result of 2D array is : ", product)

```

Output

```1st Input array :  [1 2 3 4 5]
2nd Input array :  [5 4 3 2 1]
Multiplication Result of 2D array is :  [5 8 9 8 5]

```

### 3. NumPy Program to Multiply multi-dimensional Numpy Array

In this python program example, we have used np. multiply() function to multiple 2D or multiply multi-dimensional Numpy Array

```import numpy as np
arr1 = np.array([[1, 2, 3], [4, 5, 6]])
arr2 = np.array([[6, 5, 4], [3, 2, 1]])

print ("1st Input array : ", arr1)
print ("2nd Input array : ", arr2)

product = np.multiply(arr1, arr2)
print ("Multiplication Result of 2D array is : ", product)

```

Output

```1st Input array :  [[1 2 3]
[4 5 6]]
2nd Input array :  [[6 5 4]
[3
2 1]]
Multiplication Result of 2D array is :  [[ 6 10 12]
[12 10  6]]

```

### 4.Multiply Two Numpy Arrays With Different Shapes?

We can not multiply Two Numpy Arrays With Different Shapes by using multiply() function. If you will try to do this then it will give you an error like this:ValueError: operands could not be broadcast together with shapes (2,3) (2,).

### 5.How to do element wise multiplication in numpy

In this python program example, we are doing element-wise mutiplication of numpy arrays.

```import numpy as np
arr1 = np.array([[1, 2, 3], [4, 5, 6]])
arr2 = np.array([[6, 5, 4], [3, 2, 1]])

print ("1st Input array : ", arr1)
print ("2nd Input array : ", arr2)

product = np.multiply(arr1, arr2)
print ("element wise mutiplication of numpy array : ", product)
```

Output

``` [4 5 6]]
2nd Input array :  [[6 5 4]
[3 2 1]]
element wise mutiplication of numpy array :  [[ 6 10 12]
[12 10  6]]
```