# NumPy subtract()

Summary: in this tutorial, you’ll learn how to use the numpy `subtract()` function or the – operator to find the difference between two equal-sized arrays.

## Introduction to the Numpy subtract function

The `-` or `subtract()` function returns the difference between two equal-sized arrays by performing element-wise subtractions.

Let’s take some examples of using the `-` operator and `subtract()` function.

### Using NumPy subtract() function and – operator to find the difference between two 1D arrays

The following example uses the `-` operator to find the difference between two 1-D arrays:

`import numpy as np`

a = np.array([1, 2])
b = np.array([3, 4])

c = b – a
print(c)

Output:

`[2 2]`

How it works.

First, create two 1D arrays with two numbers in each:

`a = np.array([1, 2]) b = np.array([2, 3])`

Second, find the difference between the array b and array a by using the `-` operator:

`c = a - b`

The `-` operator returns the difference between each element of array b with the corresponding element of array a:

`[2-1, 3-2] = [1,1]`

Similarly, you can use the `subtract()` function to find the difference between two 1D arrays like this:

`import numpy as np`

a = np.array([1, 2])
b = np.array([3, 4])

c = np.subtract(b, a)

print(c)

Output:

`[2 2]`

### Using NumPy subtract function and – operator to find the difference between two 2D arrays example

The following example uses the `-` operator to find the difference between two 2D arrays:

`import numpy as np`

a = np.array([[1, 2], [3, 4]])
b = np.array([[5, 6], [7, 8]])

c = b – a
print(c)

Output:

`[[4 4] [4 4]]`

In this example, the `-` operator performs element-wise subtraction:

`[[ 5-1 6-2] [7-3 8-4]]`

Likewise, you can use the `subtract()` function to find the difference between two 2D arrays:

`import numpy as np`

a = np.array([[1, 2], [3, 4]])
b = np.array([[5, 6], [7, 8]])

c = np.subtract(b, a)
print(c)

Output:

`[[4 4] [4 4]]`

## Summary

• Use the `-` operator or `subtract()` function to find the difference between two equal-sized arrays.