如何编写函数以并行执行（python）？

Question

Sorry if I don't know how to give this a proper title. I just cant explain properly since english is not my first language but i'll give it a try.

So this is my code structure

while True:
    get_frame()
    process_frame()
    show_frame()

it executes this way: get_frame() --> process_frame() --> show_frame() --> get_frame()

so it only get frames after processing and showing the frame which takes too much time. What I really want is for the get_frame() to execute again when process_frame() executes, and for the process_frame() to execute again when show_frame() executes, and so on

Something like this: get_frame() --> process_frame()&get_frame() --> show_frame()&process_frame()&get_frame() --> and so on

Answer 1

Ok, since your question lacks a Minimal, Complete and Verifiable example I am going to have to guess on what it is exactly that you want to achieve.

However, my hunch is that you are trying to accomplish something along the lines of:

#!/usr/bin/env python3
# -*- coding: UTF-8 -*-

from threading import Thread

class GetFrame(Thread):

    def __init__(self, frame):

        self.frame = frame
        Thread.__init__(self)
        self.start()

    def run(self):

        received_frame = # Code to get frame

        ProcessFrame(received_frame)


class ProcessFrame(object):

    def __init__(self, frame):

        self.frame = frame
        Thread.__init__(self)
        self.start()

    def run(self):

        processed_frame = # Code to process frame
        ShowFrame(processed_frame)

class ShowFrame(object):

    def __init__(self, frame):

        self.frame = frame
        Thread.__init__(self)
        self.start()

    def run(self):

        # Code to show frame

for frame in frame_list:

    instance = GetFrame(frame)

Please note though that if you have many frames you want to process their might be far more efficient ways to achieve what you are after. My setup basically just shows a very basic setup that could be used to get, process and show many frames simultaneously.

If you want more control over your threads you could take a look at python's queue module .