我的 python function 中的 for 循环没有运行

Question

My for loop inside the function "play()" is not getting executed at runtime.

def play():
    print("1")
    for files in os.listdir(os.getcwd()):
        if files.endswith("mp3"):
            print("2")
            pygame.mixer.Sound.play(files)
        else:
            continue
play()

Answer 1

pygame seems a poor choice for a media player, unless you have it loaded for another reason.
I'd suggest you look on SO for vlc.py or Gstreamer examples.
That said, the player can only play one thing at a time, so you can't just throw the contents of your disk at it and you need to check if you found anything at all.
Try something like this as your starting point:

import os
import pygame.mixer
import time

pygame.mixer.init(frequency=44100)
def play():
    loaded = 0
    queue = []
    path = os.getcwd()
    for mp3 in os.listdir(path):
        if mp3.endswith("mp3"):
            if loaded == 0:
                pygame.mixer.music.load(mp3)
                loaded = 1
                print('Playing:', mp3)
            else:
                print('Queued:', mp3)
                queue.append(mp3)                

    print("\nAudio Queued: ", str(len(queue)), "\n")
    running = True
    if loaded:
        pygame.mixer.music.play()
        while running:
            time.sleep(1)
            if not pygame.mixer.music.get_busy():
                if len(queue):
                    pygame.mixer.music.load(queue[0])
                    print('Playing:', queue[0])
                    queue.pop(0)
                    pygame.mixer.music.play()
                else:
                    running = False
    else:
        print("No media found in ", path)
if __name__ == '__main__':
    play()

Beware the frequency setting in the init .
You may have to load other modules to determine what it is for each audio item and re-init the player, to enforce it. Otherwise, you may find things playing at the wrong tempo.

Answer 2

First of all, you don't need the argument 'nulll'. Second, your function does execute (Make sure you have.mp3 files in your directory):

def play():
    print("1")
    for file in os.listdir(os.getcwd()):
        if file.endswith("mp3"):
            print(file)
            # pygame.mixer.Sound.play(files)
        else:
            continue
play()

Finally if you are iterating through a loop you should name your for variable like a single element in a list.

Answer 3

Okay, so just reproduced the error. Found out you were missing on few imports/ functions. Here is the code you need to run.

import os
import pygame.mixer
pygame.mixer.init()
def play():
    print("1")
    for files in os.listdir(os.getcwd()):
        if files.endswith("mp3"):
            print(files)
            pygame.mixer.music.load(files)
            pygame.mixer.music.play()
        else:
            print("No such file exists")

if __name__ == '__main__':
    play()

I guess you were not initiating the mixer function. Also make sure you have mp3 file in your cwd. You can print cwd and ensure mp3 file is there.

You dont need nulll and print("1") as well.