Boolean indexing in NumPy - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to select elements greater than 5 from the array.

NumPy

import numpy as np
arr = np.array([1, 6, 3, 8, 4])
result = arr[arr [1] 5]
print(result)

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

A<

B==

C>

D!=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '==' instead of '>' selects only elements equal to 5.

Using '<' selects elements less than 5, which is not correct here.

Using arr > 5 creates a boolean mask selecting elements greater than 5.

2fill in blank

medium

Complete the code to select elements that are even numbers from the array.

NumPy

import numpy as np
arr = np.array([2, 7, 4, 9, 6])
even_elements = arr[arr [1] 2 == 0]
print(even_elements)

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

A//

B**

C+

D%

Attempts:

3 left

💡 Hint

Common Mistakes

Using '//' performs floor division, not remainder.

Using '**' is exponentiation, which is not needed here.

The modulo operator % checks the remainder. Even numbers have remainder 0 when divided by 2.

3fill in blank

hard

Fix the error in the code to select elements less than 10.

NumPy

import numpy as np
arr = np.array([12, 5, 8, 15, 3])
selected = arr[arr [1] 10]
print(selected)

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

A<

B==

C!=

D>=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=>' causes syntax error.

Using '==' selects only elements equal to 10, not less than.

The correct operator to select elements less than 10 is <.

4fill in blank

hard

Fill both blanks to create a dictionary of words and their lengths for words longer than 3 characters.

NumPy

words = ['apple', 'bat', 'carrot', 'dog']
lengths = {word: [1] for word in words if [2] > 3}
print(lengths)

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Alen(word)

Bword

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'word' instead of 'len(word)' for length calculation.

Filtering by 'word > 3' which is invalid.

Use len(word) to get the length and filter words with length greater than 3.

5fill in blank

hard

Fill in the blank to create a dictionary of uppercase words and their lengths for words longer than 3 characters.

NumPy

words = ['apple', 'bat', 'carrot', 'dog']
result = [1]
print(result)

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

A{word.upper(): len(word) for word in words if len(word) > 3}

Blen(word)

C>

D{word.upper()

Attempts:

3 left

💡 Hint

Common Mistakes

Not using uppercase for keys.

Filtering incorrectly or missing length check.

The dictionary comprehension uses word.upper() as keys, len(word) as values, and filters words with length greater than 3.