Python Practice Problems

Python practice problems help beginners to become experts in a python programming language with a small amount of practice effort.

Word lengths as a dictionary

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Python Practice › List Programs › Program 96

Word lengths as a dictionary

EasyList Programs · 96 of 100

Write a Python program to build a dictionary of each word and its length.

Input
["Hello", "student", "are", "learning", "Python", "Its", "Language"]
Output
{'Hello': 5, 'student': 7, 'are': 3, 'learning': 8, 'Python': 6, 'Its': 3, 'Language': 8}

Approach

  1. A dict comprehension.

Solution

Python
words = ["Hello", "student", "are", "learning", "Python", "Its", "Language"]print({w: len(w) for w in words})
Output
{'Hello': 5, 'student': 7, 'are': 3, 'learning': 8, 'Python': 6, 'Its': 3, 'Language': 8}

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Remove the 2nd character of each word

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Python Practice › List Programs › Program 95

Remove the 2nd character of each word

EasyList Programs · 95 of 100

Write a Python program to remove the 2nd character of each word.

Input
["Hello", "student", "are", "learning", "Python", "Its", "Python", "Language"]
Output
['Hllo', 'sudent', 'ae', 'larning', 'Pthon', 'Is', 'Pthon', 'Lnguage']

Approach

  1. Join the slices before and after index 1.

Solution

Python
words = ["Hello", "student", "are", "learning", "Python", "Its", "Python", "Language"]print([w[0] + w[2:] for w in words])
Output
['Hllo', 'sudent', 'ae', 'larning', 'Pthon', 'Is', 'Pthon', 'Lnguage']

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More list programs

#96EasyWord lengths as a dictionary#97EasyRemove repeated dictionaries#98MediumDecode a run-length encoded list#99EasyRound every number and sum

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Capitalise the 3rd character of each word

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Python Practice › List Programs › Program 94

Capitalise the 3rd character of each word

EasyList Programs · 94 of 100

Write a Python program to make the 3rd character of each word uppercase.

Input
["Hello", "student", "are", "learning", "Python", "Its", "Python", "Language"]
Output
['HeLlo', 'stUdent', 'arE', 'leArning', 'PyThon', 'ItS', 'PyThon', 'LaNguage']

Approach

  1. Index 2 is the 3rd character; rebuild the word around it.

Solution

Python
words = ["Hello", "student", "are", "learning", "Python", "Its", "Python", "Language"]print([w[:2] + w[2].upper() + w[3:] if len(w) > 2 else w for w in words])
Output
['HeLlo', 'stUdent', 'arE', 'leArning', 'PyThon', 'ItS', 'PyThon', 'LaNguage']
Note

The original sample changed the 4th character (“HelLo”). The 3rd character is index 2, which gives “HeLlo”.

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More list programs

#95EasyRemove the 2nd character of each word#96EasyWord lengths as a dictionary#97EasyRemove repeated dictionaries#98MediumDecode a run-length encoded list

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Replace a word in a list

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Python Practice › List Programs › Program 93

Replace a word in a list

EasyList Programs · 93 of 100

Write a Python program to replace “Java” with “Python” in a list of words.

Input
["Hello", "student", "are", "learning", "Java", "Its", "Java", "Language"]
Output
['Hello', 'student', 'are', 'learning', 'Python', 'Its', 'Python', 'Language']

Approach

  1. Map each word, replacing the match.

Solution

Python
words = ["Hello", "student", "are", "learning", "Java", "Its", "Java", "Language"]print(["Python" if w == "Java" else w for w in words])
Output
['Hello', 'student', 'are', 'learning', 'Python', 'Its', 'Python', 'Language']

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Dictionary from sublists

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Python Practice › List Programs › Program 92

Dictionary from sublists

EasyList Programs · 92 of 100

Write a Python program to create a dictionary from [key, value] sublists.

Input
[["a", 5], ["b", 8], ["c", 11], ["d", 14], ["e", 23]]
Output
{'a': 5, 'b': 8, 'c': 11, 'd': 14, 'e': 23}

Approach

  1. dict() accepts pairs directly.

Solution

Python
print(dict([["a", 5], ["b", 8], ["c", 11], ["d", 14], ["e", 23]]))
Output
{'a': 5, 'b': 8, 'c': 11, 'd': 14, 'e': 23}

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Tuples to sublists

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Python Practice › List Programs › Program 91

Tuples to sublists

EasyList Programs · 91 of 100

Write a Python program to convert the tuples in a list into lists.

Input
[(3, 5), (6, 8), (8, 11), (12, 14), (17, 23)]
Output
[[3, 5], [6, 8], [8, 11], [12, 14], [17, 23]]

Approach

  1. list(t) for each tuple.

Solution

Python
data = [(3, 5), (6, 8), (8, 11), (12, 14), (17, 23)]print([list(t) for t in data])
Output
[[3, 5], [6, 8], [8, 11], [12, 14], [17, 23]]

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Flatten a nested list

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Python Practice › List Programs › Program 90

Flatten a nested list

MediumList Programs · 90 of 100

Write a Python program to flatten a nested list.

Input
[0, 12, [22, 32], 42, 52, [62, 72, 82], [92, 102, 112, 122]]
Output
[0, 12, 22, 32, 42, 52, 62, 72, 82, 92, 102, 112, 122]

Approach

  1. Add plain items directly and the contents of sub-lists one by one (recursively for deeper nesting).

Solution

Python
def flatten(items):    flat = []    for item in items:        if isinstance(item, list):            flat.extend(flatten(item))        else:            flat.append(item)    return flat print(flatten([0, 12, [22, 32], 42, 52, [62, 72, 82], [92, 102, 112, 122]]))
Output
[0, 12, 22, 32, 42, 52, 62, 72, 82, 92, 102, 112, 122]

Line by line

Lines 4-5

A sub-list is flattened by calling the same function on it, so any depth works.

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Palindrome strings in a list

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Python Practice › List Programs › Program 89

Palindrome strings in a list

EasyList Programs · 89 of 100

Write a Python program to get the palindrome strings from a list.

Input
["data", "python", "oko", "test", "ete"]
Output
['oko', 'ete']

Approach

  1. Keep words equal to their reverse.

Solution

Python
words = ["data", "python", "oko", "test", "ete"]print([w for w in words if w == w[::-1]])
Output
['oko', 'ete']

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More list programs

#90MediumFlatten a nested list#91EasyTuples to sublists#92EasyDictionary from sublists#93EasyReplace a word in a list

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Percentage from marks

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Python Practice › List Programs › Program 88

Percentage from marks

EasyList Programs · 88 of 100

Write a Python program to calculate the percentage from a list of marks out of 100 each.

Input
[80, 50, 70, 90, 95]
Output
77%

Approach

  1. Total obtained divided by total possible, times 100.

Solution

Python
marks = [80, 50, 70, 90, 95]percent = sum(marks) / (len(marks) * 100) * 100print(f"{percent:.0f}%")
Output
77%

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Bill per fruit purchased

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Python Practice › List Programs › Program 87

Bill per fruit purchased

MediumList Programs · 87 of 100

Write a Python program to calculate the bill for each fruit purchased, from a price list and a quantity list.

Input
prices [["apple", 30], ["mango", 50], ["banana", 20], ["lichi", 50]]; bought [["apple", 2], ["mango", 10]]
Output
Fruit: Apple    Bill: 60
Fruit: Mango    Bill: 500
Total: 560

Approach

  1. Turn the price list into a dict for lookup, then multiply price by quantity.

Solution

Python
prices = dict([["apple", 30], ["mango", 50], ["banana", 20], ["lichi", 50]])bought = [["apple", 2], ["mango", 10]]total = 0for fruit, qty in bought:    bill = prices[fruit] * qty    total += bill    print(f"Fruit: {fruit.capitalize():8} Bill: {bill}")print("Total:", total)
Output
Fruit: Apple    Bill: 60
Fruit: Mango    Bill: 500
Total: 560

Line by line

Line 1

dict() accepts a list of [key, value] pairs.

Learn the concept

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More list programs

#88EasyPercentage from marks#89EasyPalindrome strings in a list#90MediumFlatten a nested list#91EasyTuples to sublists

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