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Concurrency & performance

asyncio, threading, multiprocessing, and profiling-friendly performance patterns.

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Concurrency & performance easy

How to use ThreadPoolExecutor for concurrent tasks in Python

Run blocking functions in parallel with ThreadPoolExecutor and as_completed, cutting total runtime from 5 sequential sleeps to about 1 second.

concurrency threadpoolexecutor parallel
Python 
import time
from concurrent.futures import ThreadPoolExecutor, as_completed


def fetch_data(item):
    """Simulate a slow operation with a fixed delay."""
    time.sleep(0.2)
    return item * 2


def main():
    items = [1, 2, 3, 4, 5]
    start = time.perf_counter()

    with ThreadPoolExecutor(max_workers=3) as ex…
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