Reference library

Comprehensions & generators

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

5 matches

Drop n items then yield rest generator

A generator that skips the first n items of an iterable and then yields the remaining items one by one.

def drop(n, items):
    """Yield every item except the first n from items."""
    it = iter(items)
    for _ in range(n):
        next(it, None)  # skip first n items
    yield from it


if __name__ == "__main__":
    numbers = [10, 20, 30, 40, 50]
    result = list(drop(2, numbers))
    print(result)

11 0 Open

Comprehensions & generators easy

How to Create a Pairwise Generator with zip and tee in Python

Build a memory-efficient generator that yields successive overlapping pairs from any iterable using zip and tee.

itertools generators zip

Python

from itertools import tee


def pairwise(iterable):
    """Yield successive overlapping pairs from iterable."""
    a, b = tee(iterable)
    next(b, None)
    return zip(a, b)


if __name__ == "__main__":
    values = [1, 2, 3, 4, 5]
    print(list(pairwise(values)))
    print(list(pairwise("hello")))

15 0 Open

Comprehensions & generators easy

How to Implement takewhile Generator in Python

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

generator takewhile iteration

Python

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 Merge Multiple Iterables with a Generator in Python

This code defines a generator function that 'chains' or merges multiple iterables into a single iterator, which is then converted to a list.

generators yield-from iterables

Python

def chain(*iterables):
    for iterable in iterables:
        yield from iterable

def main():
    list1 = [1, 2, 3]
    tuple1 = (4, 5)
    set1 = {6, 7}
    string1 = "89"

    result = list(chain(list1, tuple1, set1, string1))
    print(result)

if __name__ == "__main__":
    main()

12 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}")

13 0 Open

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