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Comprehensions & generators

List/dict/set comprehensions, generator expressions, and lazy iteration.

4 matches

How to Implement takewhile Generator in Python

A generator that yields items from an iterable until a condition fails, like itertools.takewhile.

def takewhile(predicate, iterable):
    for item in iterable:
        if not predicate(item):
            break
        yield item

if __name__ == "__main__":
    numbers = [1, 2, 3, 4, 5, 1, 2, 3]
    result = list(takewhile(lambda x: x < 4, numbers))
    print(result)

13 0 Open

Comprehensions & generators easy

How to filter even numbers with a Python list comprehension

Build a new list of only the even numbers from 1 to 20 using a single list comprehension with a filter condition.

list comprehension even numbers filtering

Python

even_numbers = [num for num in range(1, 21) if num % 2 == 0]
print(even_numbers)

12 0 Open

Comprehensions & generators easy

How to skip items until a condition is met in Python

Use itertools.dropwhile to skip leading elements while a predicate returns true, then yield the rest of the sequence unchanged.

itertools generators dropwhile

Python

def is_negative(x):
    return x < 0

numbers = [-3, -1, 0, 5, 2, -8, 7]
result = list(itertools.dropwhile(is_negative, numbers))
print(f"Original: {numbers}")
print(f"After dropwhile: {result}")

13 0 Open

Comprehensions & generators easy

List Comprehension to Filter Even Numbers in Python

Creates a new list containing only the even numbers from an existing list using a list comprehension with a condition.

list comprehension filtering even numbers

Python

numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
even_numbers = [n for n in numbers if n % 2 == 0]
print(f"Original: {numbers}")
print(f"Even numbers: {even_numbers}")

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