for — Intermediate Playground

Starts a loop that iterates over a sequence or iterable

Python Playground

# Basic comprehension
squares = [x**2 for x in range(10)]
print(squares)

# With filter
evens = [x for x in range(20) if x % 2 == 0]
print(evens)

# Nested comprehension (matrix)
matrix = [[i * j for j in range(1, 4)] for i in range(1, 4)]
for row in matrix:
    print(row)

# Dict comprehension
word = "mississippi"
freq = {ch: word.count(ch) for ch in set(word)}
print(freq)

Output

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Comprehensions are syntactic sugar for common for-loop-and-append patterns. They are often faster because the append is optimized internally.

Challenge

Try modifying the code above to explore different behaviors. Can you extend the example to handle a new use case?

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