# NumPy reshape()

Summary: in this tutorial, you’ll learn how to use the numpy `reshape()` function to change the shape of an array.

## Introduction to the numpy reshape() function

A shape of an array stores the number of dimensions (or axes) and the number of elements on each dimension. The `shape` property returns a tuple that describes the shape of an array.

The `reshape()` function changes the shape of an array without changing its elements. Here’s the syntax of the `reshape()` function:

`numpy.reshape(a, newshape, order='C')`

Code language: Python (python)

In this syntax, the `reshape()` function changes the shape of the array `a` to the `newshape` but keep the number of elements the same.

The `reshape()` function is equivalent to calling the `reshape()` method on the array a:

`a.reshape(newshape, order='C')`

Code language: Python (python)

## NumPy reshape() function examples

Let’s take some examples of using the `reshape()` function.

### 1) Using numpy reshape() function with 1-D array example

The following example uses the numpy `reshape()` function to change a 1-D array with 4 elements to a 2-D array:

`import numpy as npa = np.arange(1, 5) print(a)`

`b = np.reshape(a, (2, 2)) print(b)`

Code language: Python (python)

Output:

`[1 2 3 4] [[1 2] [3 4]]`

Code language: Python (python)

How it works.

First, create a 1-D array with four numbers from 1 to 4 by using the `arange()` function:

`a = np.arange(1, 5) print(a)`

Code language: Python (python)

Second, change the shape of array a to an array with two dimensions, each dimension has 2 elements:

`b = np.reshape(a, (2, 2)) print(b)`

Code language: Python (python)

### 2) Numpy reshape() returns a view

Note that array b is a view of array a. It means that if you change an element of array b, the change is reflected in array a. For example:

`import numpy as npa = np.arange(1, 5) b = np.reshape(a, (2, 2))# change the element [0,0] b[0, 0] = 0`

`print(b) print(a)`

Code language: Python (python)

Output:

`[[0 2] [3 4]] [0 2 3 4]`

Code language: Python (python)

In this example, we change the element at index [0,0] in the array b. The change is also reflected in the array a.

## Summary

• Use the numpy `reshape()` function to change the shape of an array without changing its elements.
• You can change the shape of an array as long as the number of elements is the same.