In-depth analysis of python-coroutines

In Python, a coroutine is a special type of function used to support asynchronous programming. Unlike ordinary functions, coroutines use yieldthe statement to suspend execution and resume execution at some later point. This enables coroutines to perform asynchronous tasks without blocking the entire program.

For example, suppose you want to write a function that reads each line of a file and returns the current line's content after reading each line. With coroutines, you can write:

def read_file(filename):
    with open(filename, "r") as f:
        for line in f:
            yield line

for line in read_file("myfile.txt"):
    print(line)

This code opens the file myfile.txt, reads each yieldline , and pauses execution. At some later point, the program resumes execution until yieldthe statement . This way, the program can read each line of the file without blocking the entire program.

Coroutines can also receive parameters and return results to the caller when execution is suspended. For example, you can write a coroutine to calculate the Fibonacci sequence:

def fibonacci():
    a, b = 0, 1
    while True:
        yield a
        a, b = b, a + b

for i, number in enumerate(fibonacci()):
    print(f"{i}: {number}")
    if i > 9:
        break

In Python, coroutines asynccan awaitbe written using and . This method is very similar to traditional coroutines, but it is more convenient to use.

For example, you asynccould awaitrewrite the file reading example above using and :

import asyncio

async def read_file(filename):
    with open(filename, "r") as f:
        for line in f:
            yield line

async def main():
    async for line in read_file("myfile.txt"):
        print(line)

await main()

The effect of this code is exactly the same as the code using traditional coroutines, but it is more convenient to use.

In Python, coroutines can be combined with asynchronous I/O, which makes coroutines a very powerful tool. For example, you can use coroutines to access a network interface asynchronously, or to perform database queries without blocking the entire program.

In general, coroutines are a very powerful tool that can help you write asynchronous code more easily. If you want to learn more about Python coroutines, you can refer to the relevant chapters in the official Python documentation, or view related tutorials on the Internet.

Hope this blog can help you!

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In-depth analysis of python-coroutines

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