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Comprehensions & generators

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

3 matches

Build a lazy generator to read file lines in Python

Create a generator function that yields file lines one at a time, avoiding loading the entire file into memory, and demonstrate its lazy processing.

generator file-io lazy

Python

def lazy_lines(filepath):
    """Yield lines from a file one at a time without loading the whole file into memory."""
    with open(filepath, 'r', encoding='utf-8') as file:
        for line in file:
            yield line.rstrip('\n')


if __name__ == "__main__":
    # Create a sample file to demonstrate
    sample_c…

14 0 Open

Comprehensions & generators easy

Generate UUID4 Values with a Python Generator

This code defines a generator function that yields mock UUID4 values, allowing you to stream unique identifiers one at a time.

uuid generators streaming

Python

import uuid

def generate_uuids(count=5):
    """Generate a stream of mock UUID4 values."""
    for _ in range(count):
        yield uuid.uuid4()

if __name__ == "__main__":
    # Generate and print 5 UUIDs
    for uid in generate_uuids(5):
        print(uid)

15 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

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