Reference library

Comprehensions & generators

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

4 matches

Chunk an Iterable into Batches with a Generator in Python

Yield fixed-size batches from any iterable lazily using itertools.islice inside a generator function.

from itertools import islice

def chunked(iterable, size):
    iterator = iter(iterable)
    while True:
        batch = list(islice(iterator, size))
        if not batch:
            break
        yield batch

if __name__ == "__main__":
    data = range(10)
    for batch in chunked(data, 3):
        print(batch)

14 0 Open

Comprehensions & generators easy

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.

generators iterators drop

Python

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 Parse CSV Rows as Generator Dicts in Python

Reads a CSV file and yields each row as a dictionary one at a time using a generator, so the file is processed lazily.

csv generator parsing

Python

import csv
from pathlib import Path

def csv_to_dicts(filepath):
    with open(filepath, mode="r", newline="", encoding="utf-8") as file:
        reader = csv.DictReader(file)
        for row in reader:
            yield row

if __name__ == "__main__":
    sample_csv = Path("sample_data.csv")
    sample_csv.write_text…

13 0 Open

Comprehensions & generators easy

How to Repeat a Generator Cycle Single Value in Python

Build a generator that repeats a single value across multiple cycles, each cycle adding an extra repetition to mark its completion.

generators loops repeat

Python

def repeat_with_cycle(value, cycle_limit, repetitions):
    """
    Repeats a single value until reaching a cycle limit,
    then yields the value one more time to demonstrate a full cycle.
    
    Args:
        value: The single value to repeat.
        cycle_limit: Number of repetitions per cycle.
        repetitio…

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