Concurrency & performance
asyncio, threading, multiprocessing, and profiling-friendly performance patterns.
How to Parse JSON Files in Parallel with Python ThreadPoolExecutor
Load and transform JSON records from multiple files concurrently using ThreadPoolExecutor for faster I/O-bound parsing.
import time
from concurrent.futures import ThreadPoolExecutor
import json
def load_json_file(path):
with open(path, 'r') as f:
return json.load(f)
def transform_record(record):
record['full_name'] = f"{record.pop('first_name', '')} {record.pop('last_name', '')}".strip()
record['score'] = int(reco…
How to Share a Queue Between Processes in Python
Use multiprocessing.Queue to pass work from a producer process to multiple consumer processes, coordinating with a sentinel stop message.
import multiprocessing
import time
def producer(queue, items):
for item in items:
queue.put(item)
time.sleep(0.1)
queue.put("STOP")
def consumer(queue, name):
while True:
item = queue.get()
if item == "STOP":
break
print(f"{name} processed: {item}")
…
How to Use asyncio Lock to Protect a Shared Counter in Python
This code demonstrates how to use an asyncio.Lock to safely increment a shared counter from multiple concurrent coroutines.
import asyncio
async def increment(counter, lock, increments):
for _ in range(increments):
async with lock:
counter[0] += 1
async def main():
counter = [0]
lock = asyncio.Lock()
tasks = [
increment(counter, lock, 1000)
for _ in range(5)
]
await asyncio.gath…
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Concurrency & performance — Python code examples
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This page collects concurrency & performance snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.
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