np.newaxis for adding dimensions in NumPy - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a new axis to the 1D array to make it 2D.

NumPy

import numpy as np
arr = np.array([1, 2, 3])
new_arr = arr[1]
print(new_arr.shape)

Drag options to blanks, or click blank then click option'

A[np.newaxis, np.newaxis]

B[np.newaxis, :]

C[np.newaxis]

D[:, np.newaxis]

Attempts:

3 left

💡 Hint

Common Mistakes

Using [np.newaxis] alone does not add a new axis correctly.

Adding np.newaxis in the wrong position changes the shape differently.

Using [:, np.newaxis] adds a new axis as a column, changing shape from (3,) to (3, 1).

2fill in blank

medium

Complete the code to add a new axis at the start of the array shape.

NumPy

import numpy as np
arr = np.array([4, 5, 6])
new_arr = arr[1]
print(new_arr.shape)

Drag options to blanks, or click blank then click option'

A[np.newaxis, :]

B[:, np.newaxis]

C[np.newaxis]

D[np.newaxis, np.newaxis]

Attempts:

3 left

💡 Hint

Common Mistakes

Placing np.newaxis after the colon adds the axis at the end, not the start.

Using just [np.newaxis] does not specify the position clearly.

Using [np.newaxis, :] adds a new axis at the start, changing shape from (3,) to (1, 3).

3fill in blank

hard

Fix the error in the code to correctly add a new axis to the array.

NumPy

import numpy as np
arr = np.array([7, 8, 9])
new_arr = arr[1]
print(new_arr.shape)

Drag options to blanks, or click blank then click option'

A[np.newaxis]

B[np.newaxis, :]

C[:, np.newaxis]

Dnp.newaxis

Attempts:

3 left

💡 Hint

Common Mistakes

Using np.newaxis without slicing causes errors.

Placing np.newaxis inside brackets incorrectly changes the shape.

The correct way to add a new axis as a column is [:, np.newaxis]. Using np.newaxis alone or in wrong positions causes errors or wrong shapes.

4fill in blank

hard

Fill both blanks to create a 3D array by adding two new axes to the 1D array.

NumPy

import numpy as np
arr = np.array([10, 20, 30])
new_arr = arr[1][2]
print(new_arr.shape)

Drag options to blanks, or click blank then click option'

A[np.newaxis]

B[:, np.newaxis]

C[np.newaxis, np.newaxis]

D[np.newaxis, :]

Attempts:

3 left

💡 Hint

Common Mistakes

Using combined axes like [np.newaxis, np.newaxis] once instead of chaining twice.

Mixing slicing and brackets incorrectly.

Adding [np.newaxis] twice adds two new axes, changing shape from (3,) to (1, 1, 3).

5fill in blank

hard

Fill all three blanks to create a 4D array with shape (1, 1, 1, 3) from a 1D array.

NumPy

import numpy as np
arr = np.array([100, 200, 300])
new_arr = arr[1][2][3]
print(new_arr.shape)

Drag options to blanks, or click blank then click option'

A[np.newaxis]

B[:, np.newaxis]

C[np.newaxis, :]

D[np.newaxis, np.newaxis]

Attempts:

3 left

💡 Hint

Common Mistakes

Adding axes in wrong order changes the shape.

Using combined axes incorrectly.

Using [np.newaxis, np.newaxis] adds two new axes at the start, then [np.newaxis] adds another, and [:, np.newaxis] adds a new axis as column, resulting in shape (1, 1, 1, 3).