Matrix creation and operations in SciPy - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a 3x3 identity matrix using NumPy.

SciPy

from numpy import eye
matrix = eye([1])

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A5

B2

C4

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using a size other than 3 will create a matrix of wrong dimensions.

Confusing eye with ones or zeros.

The eye function creates an identity matrix of the given size. Here, a 3x3 identity matrix is created by passing 3.

2fill in blank

medium

Complete the code to create a 2x4 matrix of zeros using NumPy.

SciPy

from numpy import zeros
matrix = zeros(([1]))

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A2, 2

B4, 2

C2, 4

D3, 4

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping rows and columns in the tuple.

Passing separate arguments instead of a tuple.

The zeros function creates a matrix filled with zeros. Passing the shape as a tuple (2, 4) creates a 2 rows by 4 columns matrix.

3fill in blank

hard

Fix the error in the code to multiply two matrices using NumPy.

SciPy

from numpy import array
A = array([[1, 2], [3, 4]])
B = array([[5, 6], [7, 8]])
result = A [1] B

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A@

B*

Cdot

D+

Attempts:

3 left

💡 Hint

Common Mistakes

Using * instead of @ for matrix multiplication.

Trying to use dot as an operator instead of a method.

Matrix multiplication in Python with arrays uses the @ operator. Using * does element-wise multiplication, which is not matrix multiplication.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that maps each word to its length only if the length is greater than 3.

SciPy

words = ['data', 'science', 'is', 'fun']
lengths = {word: [1] for word in words if [2]

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Alen(word)

Blen(word) > 3

Cword.startswith('s')

Dword.upper()

Attempts:

3 left

💡 Hint

Common Mistakes

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

Using a wrong condition that filters incorrectly.

The dictionary comprehension maps each word to its length using len(word). The condition len(word) > 3 filters words longer than 3 characters.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps uppercase words to their lengths only if the length is greater than 2.

SciPy

words = ['cat', 'dog', 'elephant']
result = { [1]: [2] for word in words if [3] }

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Aword.upper()

Blen(word)

Clen(word) > 2

Dword.lower()

Attempts:

3 left

💡 Hint

Common Mistakes

Using lowercase instead of uppercase for keys.

Incorrect condition that filters out all words.

The dictionary comprehension uses word.upper() as the key, len(word) as the value, and filters words with length greater than 2 using len(word) > 2.