Discover challenging Python brain teasers that test your skills and stretch your thinking. Gain insights into advanced concepts and enhance your understanding of this versatile language.

Forget Scrabble, Boggle, or Wordle. Tease your mind and test your skills with these fun brain teasers designed to stretch your thinking and expand your understanding of one of the most widely used languages out there. 

Python is simple. These puzzles are not. Good luck!

Python Brain Teasers

# Try it yourself
Try executing the code below to verify the results:

import re
from collections import defaultdict


def word_freq(text, freqs=defaultdict(int)): 
    """Calculate word frequency in text. freqs are previous frequencies"""
    for word in [w.lower() for w in re.findall(r'\w+', text)]:
        freqs[word] += 1
    return freqs


freqs1 = word_freq('Duck season. Duck!')
freqs2 = word_freq('Rabbit season. Rabbit!')
print(freqs1)
print(freqs2)

# Explanation

One of the solutions to [Puzzle 11: Click the Button](https://www.educative.io/courses/python-brain-teasers/puzzle-11-explanation) considers the fact that default arguments to a function are evaluated once when the function is defined. In this teaser, we see the difficulties of this property.

Mutable default arguments are considered bad practice, and linters such as **Flake8** or **Pylint** will mark **line 5** in this teaser code as an error.
## Solution
The solution is to use `None` as the default value and in the function itself to create the mutable default. itself to create the mutable default.

Let’s find out how mutable default arguments work in Python.

Before We Begin

Python Puzzles

Wrapping Up

Puzzle 19: Explanation

Try it yourself

Explanation