Tasks, Futures & Concurrency

asyncio.gather — Concurrent Execution in Python

0:00

0% complete

LearnStep 1 of 4

What is asyncio.gather?

Learning Objectives

•Use asyncio.gather() to run multiple coroutines concurrently
•Handle exceptions in gathered tasks with return_exceptions
•Apply asyncio.gather patterns for concurrent API calls and parallel execution

Lesson Outline

LearnStep 1/4

What is asyncio.gather?

asyncio.gather: Run Multiple Coroutines Concurrently

asyncio.gather() is one of the most important functions in Python's asyncio module. It takes multiple coroutines (or awaitables), schedules them to run concurrently, and returns all their results as a list.

This is essential when you need to perform multiple I/O operations in parallel — such as fetching data from multiple APIs, querying multiple database tables, or reading multiple files simultaneously.

Basic Usage

python

Without asyncio.gather, calling these sequentially with await would take 0.2 seconds. With gather, both run at the same time and finish in ~0.1 seconds.

Key Behaviors

Concurrent execution: All coroutines start at the same time on the event loop
Ordered results: Results are returned in the same order as the input arguments, regardless of which coroutine finishes first
Exception propagation: If any coroutine raises an exception, gather raises it immediately (unless return_exceptions=True)

Common Patterns

python