Python Practice Questions & Solutions Day 7 of Learning Python for Data Science

Test your understanding of Python Data Structure, which we learned in our previous lesson of Day 7 of Learning Python for Data Science, with these targeted practice questions.

Welcome back to Day 7 of Learning Python for Data Science journey! In the last article, we explored:

✅ Tuples
✅ dictionaries
✅ Comprehensions

Now, it’s time to solve the practice questions given in the previous article.
Each question is followed by a detailed explanation and output.

Tuples

Create a tuple with numbers and find the maximum and minimum values.

tuple1 = (243, 34, 235, 25, 252, 253, 567 ,5685, 8678)

print('Max : ', max(tuple1))
print('Min : ', min(tuple1))

Output:

Max :  8678
Min :  25

Write a program to count occurrences of an element in a tuple.

tuple1 = (243, 34, 235, 25, 25, 252, 253, 567 ,5685, 8678)

tuple1.count(25)

Output:

2

Convert a tuple of strings to a single concatenated string.

tuple_str = ('Mango', 'Banana', 'Grapes')

''.join(tuple_str)

Output:

'MangoBananaGrapes'

Check if an element exists in a tuple.

tuple_str = ('Mango', 'Banana', 'Grapes')

'Mango' in tuple_str

Output:

True

Swap two tuples without using a temporary variable.

tuple_str = ('Mango', 'Banana', 'Grapes') #creating
tuple1 = (243, 34, 235, 25, 25, 252, 253, 567 ,5685, 8678) #creating

tuple_str, tuple1 = tuple1, tuple_str # swaping

print(tuple_str)
print(tuple1)

Output:

tuple_str:  (243, 34, 235, 25, 25, 252, 253, 567, 5685, 8678)
tuple1:  ('Mango', 'Banana', 'Grapes')

Reverse a tuple

tuple_str = ('Mango', 'Banana', 'Grapes') 

tuple_str[::-1]

Output:

('Grapes', 'Banana', 'Mango')

Write a program to find common elements between two tuples.

tuple_str1 = ('Mango', 'Banana', 'Grapes') 
tuple_str2 = ('Mango', 'Guvava', 'Peach')

set(tuple_str1).intersection(set(tuple_str2))

Output:

{'Mango'}

Convert a tuple of numbers into a tuple of their squares.

tuple_n = (5, 4, 6, 7, 8, 9, 2)

tuple_square = tuple(i**2 for i in tuple_n)

print(tuple_square)

Output:

(25, 16, 36, 49, 64, 81, 4)

Merge two tuples and remove duplicates.

tuple_n = (5, 4, 6, 7, 8, 9, 2)
tuple_d = (5, 4, 34, 45, 56, 67, 8)

set(tuple_n).union(set(tuple_d)) #method 1

set(tuple_n) | set(tuple_d) #method 2

Output:

{2, 4, 5, 6, 7, 8, 9, 34, 45, 56, 67}

Write a function to return the first and last element of a tuple.

tuple_n = (5, 4, 6, 7, 8, 9, 2)

def tup_func(tuple):
    return tuple[0], tuple[-1]

tup_func(tuple_n)

Output:

(5, 2)

Dictionaries

Create a dictionary from two lists (keys and values).

keys = ['name', 'age']
values = [['John', 'Mark'], [28, 30]]

# Creating the dictionary
people_dict = dict(zip(keys, values))

print(people_dict)

Output:

{'name': ['John', 'Mark'], 'age': [28, 30]}

Write a function that returns keys with the highest values in a dictionary.

def get_max_keys(dictionary):
    if not dictionary:
        return None  # Handle empty dictionary case
    
    max_value = max(dictionary.values())  # Find the highest value
    max_keys = [key for key, value in dictionary.items() if value == max_value]  # Get all keys with max value
    
    return max_keys, max_value

# Example dictionary
num = {
    'one': 1,
    'two': 2,
    'three': 3,
    'four': 4,
    'five': 4  # Added a duplicate max value for testing
}

print(get_max_keys(num))

Output:

(['four', 'five'], 4)

Merge two dictionaries and sort by key.

num1 = {
    'one': 1,
    'two': 2,
}

num2 = {
    'three': 3,
    'four': 4
}

# Merging dictionaries
num1.update(num2)

# Sorting by keys
sorted_num1 = dict(sorted(num1.items()))

print(sorted_num1)

Output:

{'four': 4, 'one': 1, 'three': 3, 'two': 2}

Count occurrences of characters in a string using a dictionary.

string = 'banana'
count = {}

# iterating through string to create a dictionary
for i in string:
    if i in count.keys():
        count[i] += 1
    else:
        count[i] = 1

print(count)

Output:

{'b': 1, 'a': 3, 'n': 2}

Find the sum of all values in a dictionary.

num = {
    'one': 1,
    'two': 2,
    'three': 3,
    'four': 4
}

# Finding the sum of all values
sum_values = sum(num.values())

print("Sum of all values:", sum_values)

Output:

Sum of all values: 10

Remove a key from a dictionary safely.

num = {
    'one': 1,
    'two': 2,
    'three': 3,
    'four': 4
}

# Safely removing a key
removed_value = num.pop('two', None)  # Removes 'two', returns None if not found

print("Updated Dictionary:", num)
print("Removed Value:", removed_value)

Output:

Updated Dictionary: {'one': 1, 'three': 3, 'four': 4}
Removed Value: 2

Sort a dictionary by its values in ascending order.

num = {
    'four': 4,
    'three': 3,
    'two': 2,
    'one': 1  
}

# Sorting dictionary by values in ascending order
sorted_dict = dict(sorted(num.items(), key=lambda item: item[1]))

print(sorted_dict)

Output:

{'one': 1, 'two': 2, 'three': 3, 'four': 4}

Write a program to invert keys and values in a dictionary.

num = {
    'one': 1,
    'two': 2,
    'three': 3,
    'four': 4
}

new_num = {}

# interting the dictionary
for keys, value in num.items():
    new_num[value] = keys

print(new_num)

Output:

{1: 'one', 2: 'two', 3: 'three', 4: 'four'}

Create a dictionary with keys as numbers and values as their cubes.

cubes = {i : i**3 for i in range(1,5)}
print(cubes)

Output:

{1: 1, 2: 8, 3: 27, 4: 64}

Convert a dictionary to a list of tuples.

num = {
    'one': 1,
    'two': 2,
    'three': 3,
    'four': 4
}

num_tuple = tuple(num.items()) # converting to a tuple

print(num_tuple)

Output:

(('one', 1), ('two', 2), ('three', 3), ('four', 4))

Comprehensions

Generate a list of squares of even numbers from 1 to 20.

squares = [i**2 for i in range(1,21) if i % 2 == 0]
print(squares)

Output:

[4, 16, 36, 64, 100, 144, 196, 256, 324, 400]

Create a set of unique characters from a given string using comprehension.

string = 'banana'

unique_char = {i for i in string} #creating a set

print(unique_char)

Output:

{'a', 'n', 'b'}

Write a dictionary comprehension to filter out keys that have even values.

num = {
    'one' : 1,
    'two' : 2,
    'three' : 3,
    'four' : 4
}

eve_num = {key: value for key, value in num.items() if value % 2 == 0} # filtering the key value pairs having even value

print(eve_num)

Output:

{'two': 2, 'four': 4}

Generate a list of words that have more than 3 letters from a sentence.

sentence = 'histroy is written by winners.'

letter = [i for i in sentence.split() if len(i)>3]

print(letter)

Output:

['histroy', 'written', 'winners.']

Create a dictionary where keys are numbers from 1 to 10, and values are their factorials.

def factorial(n):
    return 1 if n == 0 else n * factorial(n - 1)

factorials = {num: factorial(num) for num in range(1, 11)}

print(factorials)

Output:

{1: 1, 2: 2, 3: 6, 4: 24, 5: 120, 6: 720, 7: 5040, 8: 40320, 9: 362880, 10: 3628800}

Extract unique words from a paragraph using set comprehension.

para = "The cat chased the mouse. The mouse ran fast, but the cat was faster. The cat jumped, and the mouse hid. The cat looked, but the mouse was gone."

unique_words = {word for word in para.split()} # extracting unique words

print(unique_words)

Output:

{'the', 'gone.', 'jumped,', 'cat', 'but', 'faster.', 'chased', 'The', 'fast,', 'ran', 'mouse.', 'mouse', 'looked,', 'hid.', 'and', 'was'}

Convert a list of tuples into a dictionary using comprehension.

lis = [('one', 1), ('two', 2), ('three', 3), ('four', 4)]

tup = {i[0]:i[1] for i in lis} # creating dictionary

print(tup)

Output:

{'one': 1, 'two': 2, 'three': 3, 'four': 4}

Generate a list of numbers that are multiples of both 3 and 5 from 1 to 100.

multiples_of_3_and_5 = [i for i in range(1, 101) if i % 3 == 0 and i % 5 == 0]

print(multiples_of_3_and_5)

Output:

[15, 30, 45, 60, 75, 90]

Create a dictionary with student names as keys and their grades as values, filtering only students with grades above 80.

students_grades = {
    'Alice': 85,
    'Bob': 78,
    'Charlie': 92,
    'David': 88,
    'Emma': 95}

filtered_students = {key : value for key, value in students_grades.items() if value >80}

print(filtered_students)

Output:

{'Alice': 85, 'Charlie': 92, 'David': 88, 'Emma': 95}

Generate a set of squares of odd numbers from 1 to 30.

squares_of_odd = {i**2 for i in range(1,31) if i % 2 != 0}

print(squares_of_odd)

Output:

{1, 121, 225, 289, 9, 169, 361, 441, 841, 81, 49, 529, 625, 729, 25}

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