Broadcasting rules in NumPy - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a 2D array of shape (3, 4) filled with ones.

NumPy

import numpy as np
arr = np.ones([1])
print(arr.shape)

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A(3, 4)

B[3, 4]

C3

D3, 4

Attempts:

3 left

💡 Hint

Common Mistakes

Using a list instead of a tuple for the shape.

Passing dimensions without parentheses.

The np.ones function expects a shape tuple, so (3, 4) is correct.

2fill in blank

medium

Complete the code to add a 1D array to each row of a 2D array using broadcasting.

NumPy

import numpy as np
A = np.array([[1, 2, 3], [4, 5, 6]])
B = np.array([10, 20, 30])
result = A [1] B
print(result)

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A+

B*

C-

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using multiplication instead of addition.

Trying to add arrays with incompatible shapes without broadcasting.

Using + adds the 1D array B to each row of A by broadcasting.

3fill in blank

hard

Fix the error in the code to multiply a (3,1) array with a (3,) array using broadcasting.

NumPy

import numpy as np
A = np.array([[1], [2], [3]])
B = np.array([10, 20, 30])
result = A [1] B
print(result)

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A-

B*

C+

D/

Attempts:

3 left

💡 Hint

Common Mistakes

Using addition or subtraction instead of multiplication.

Not understanding how broadcasting works with different shapes.

Multiplying A and B with * uses broadcasting to produce a (3,3) array.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps words to their lengths only if length is greater than 3.

NumPy

words = ['apple', 'bat', 'carrot', 'dog']
lengths = {word: [1] for word in words if [2]

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Alen(word)

Blen(word) > 3

Cword

Dlen(words)

Attempts:

3 left

💡 Hint

Common Mistakes

Using the word itself as the value instead of its length.

Incorrect condition that does not filter properly.

The dictionary comprehension maps each word to its length using len(word), filtering only words with length greater than 3.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps uppercase words to their lengths only if length is greater than 3.

NumPy

[1] = { [2]: [3] for word in words if len(word) > 3 }

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Aresult

Bword

Clen(word)

Dword.upper()

Attempts:

3 left

💡 Hint

Common Mistakes

Using the original word as key instead of uppercase.

Swapping keys and values in the dictionary.

Not assigning the dictionary to a variable.

The dictionary comprehension maps each uppercase word.upper() to its length len(word) for words longer than 3 characters, stored in result.