【问题标题】：subprocess call not working子进程调用不起作用
【发布时间】：2015-09-13 14:27:26
【问题描述】：

我这里有这段代码

pifm.py

#!/usr/bin/python

from subprocess import call

def play_old( filename ):
   call(["./pifm ", filename, "88.0", "88307"])
   return

def play_message():
    call(["./WelcomeMessage"])
    return

运行.py

#Import
import pifm
import glob, os
import random

#Setup Vars
songs = [""]
randomNum = 0

#Find Music in directory
os.chdir("Music")
for file in glob.glob("*.wav"):
    songs.append(file)

os.chdir("..")
while True:
    randomNum = random.randint(1,len(songs)-1)
    print("Playing Song: " + str(songs[randomNum]))
    pifm.play(str(songs[randomNum]))
    pifm.play_message()

每次我运行它都会抛出这个错误，我不知道为什么

Traceback (most recent call last):
  File "run.py", line 19, in <module>
    pifm.play(str(songs[randomNum]))
  File "/home/pi/PyRate-Radio/pifm.py", line 6, in play
    call(["./pifm ", filename, "88.0", "88307"])
  File "/usr/lib/python2.7/subprocess.py", line 493, in call
    return Popen(*popenargs, **kwargs).wait()
  File "/usr/lib/python2.7/subprocess.py", line 679, in __init__
    errread, errwrite)
  File "/usr/lib/python2.7/subprocess.py", line 1259, in _execute_child
    raise child_exception
OSError: [Errno 2] No such file or directory

有什么想法吗？

【问题讨论】：

Music目录的父目录下没有pifm这样的可执行文件；你使用了os.chdir('Music')，然后是os.chdir('..')。

标签： python raspberry-pi

【解决方案1】：

您只传递了 wav 文件的文件名，不包括 Music 目录名。
另请注意对调用语句的更改，文件名在双引号中以处理带空格的文件名，并且（显然）确保 2 个脚本是可执行的。

pifm.py

#!/usr/bin/python
from subprocess import call

def play( filename ):
   call("./pifm "+'"'+filename+'"'+" 88.0"+" 88307", shell=True)
   return

def play_message():
    call("./WelcomeMessage")
    return

运行.py

import pifm
import glob, os
import random

#Setup Vars
songs = [""]
randomNum = 0

#Find Music in directory
for file in glob.glob("Music/*.wav"):
    songs.append(file)

while True:
    randomNum = random.randint(1,len(songs)-1)
    print("Playing Song: " + str(songs[randomNum]))
    pifm.play(str(songs[randomNum]))
    pifm.play_message()

【讨论】：