Array indexing and slicing in Data Analysis Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to get the first element of the array.

Data Analysis Python

import numpy as np
arr = np.array([10, 20, 30, 40])
first_element = arr[[1]]
print(first_element)

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A1

B0

C-1

D4

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1 instead of 0 to access the first element.

Using an index outside the array range.

The first element in a Python array is accessed with index 0.

2fill in blank

medium

Complete the code to slice the array and get elements from index 1 to 4 (exclusive).

Data Analysis Python

import numpy as np
arr = np.array([5, 10, 15, 20, 25])
slice_arr = arr[[1]]
print(slice_arr)

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A2:5

B1:3

C0:3

D1:4

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1:3 which excludes index 3.

Using 2:5 which starts too late.

Slicing with 1:4 gets elements at indices 1, 2, and 3.

3fill in blank

hard

Fix the error in the code to correctly get the last two elements of the array.

Data Analysis Python

import numpy as np
arr = np.array([2, 4, 6, 8, 10])
last_two = arr[[1]]
print(last_two)

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A-2:

B3:5

C4:6

D-3:-1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 3:5 which works but is less flexible.

Using -3:-1 which excludes the last element.

Using -2: slices from the second last element to the end.

4fill in blank

hard

Fill both blanks to create a dictionary with words as keys and their lengths as values, but only for words longer than 3 characters.

Data Analysis Python

words = ['cat', 'house', 'tree', 'a', 'elephant']
lengths = {word: [1] for word in words if [2]
print(lengths)

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Alen(word)

Bword

Clen(word) > 3

Dword > 3

Attempts:

3 left

💡 Hint

Common Mistakes

Using word instead of len(word) for length.

Using word > 3 which compares strings incorrectly.

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

5fill in blank

hard

Fill all three blanks to create a dictionary with uppercase words as keys and their lengths as values, but only for words longer than 4 characters.

Data Analysis Python

words = ['apple', 'bat', 'carrot', 'dog', 'elephant']
result = { [1]: [2] for w in words if [3] }
print(result)

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Aw.upper()

Blen(w)

Clen(w) > 4

Dw.lower()

Attempts:

3 left

💡 Hint

Common Mistakes

Using w.lower() instead of w.upper() for keys.

Filtering with wrong length condition.

Keys are uppercase words, values are lengths, filtered by length > 4.