同时运行两个带有参数并返回列表的函数? [英] Concurrently run two functions that take parameters and return lists?
问题描述
我了解两个功能可以使用multiprocessing
或threading
模块并行运行,例如同时运行2个功能和用于并行进程的Python多处理.
I understand that two functions can run in parallel using multiprocessing
or threading
modules, e.g. Make 2 functions run at the same time and Python multiprocessing for parallel processes.
但以上示例仅使用打印功能. 是否可以运行在python中并行返回列表的函数,如果可以,怎么办?
But the above examples only use print function. Is it possible to run functions that return a list in parallel in python, if so, how?
我已经尝试过线程化
from threading import Thread
def func1(x):
return [i*i for i in x]
def func2(x):
return [i*i*i for i in x]
nums = [1,2,3,4,5]
p1 = Thread(target = func1(nums)).start()
p2 = Thread(target = func2(nums)).start()
print p1
print p2
但是我得到了以下错误:
but i got the follow error:
Exception in thread Thread-1:
Traceback (most recent call last):
File "/usr/lib/python2.7/threading.py", line 808, in __bootstrap_inner
self.run()
File "/usr/lib/python2.7/threading.py", line 761, in run
self.__target(*self.__args, **self.__kwargs)
TypeError: 'list' object is not callable
None
None
Exception in thread Thread-2:
Traceback (most recent call last):
File "/usr/lib/python2.7/threading.py", line 808, in __bootstrap_inner
self.run()
File "/usr/lib/python2.7/threading.py", line 761, in run
self.__target(*self.__args, **self.__kwargs)
TypeError: 'list' object is not callable
我尝试输入args
参数作为元组而不是变量:
I've tried inputing args
parameter as a tuple, instead of a variable:
import threading
from threading import Thread
def func1(x):
return [i*i for i in x]
def func2(x):
return [i*i*i for i in x]
nums = [1,2,3,4,5]
p1 = Thread(target = func1, args=(nums,)).start()
p2 = Thread(target = func2, args=(nums,)).start()
print p1, p2
,但仅返回None None
,所需的输出应为:
but it only returns None None
, the desired output should be:
[输出]:
[1, 4, 9, 16, 25] [1, 8, 27, 64, 125]
推荐答案
线程的目标函数无法返回值.或者,我应该说,return
值将被忽略,因此不会传递回生成线程.但是您可以执行以下几项操作:
Thread's target function cannot return a value. Or, I should say, the return
value is ignored and as such, not communicated back to spawning thread. But here's a couple things you can do:
1)使用Queue.Queue
通讯回生成线程.注意原始功能的包装:
1) Communicate back to spawning thread using Queue.Queue
. Note the wrapper around the original functions:
from threading import Thread
from Queue import Queue
def func1(x):
return [i*i for i in x]
def func2(x):
return [i*i*i for i in x]
nums = [1,2,3,4,5]
def wrapper(func, arg, queue):
queue.put(func(arg))
q1, q2 = Queue(), Queue()
Thread(target=wrapper, args=(func1, nums, q1)).start()
Thread(target=wrapper, args=(func2, nums, q2)).start()
print q1.get(), q2.get()
2)使用global
访问线程中的结果列表以及生成过程:
2) Use global
to access result lists in your threads, as well as the spawning process:
from threading import Thread
list1=list()
list2=list()
def func1(x):
global list1
list1 = [i*i for i in x]
def func2(x):
global list2
list2 = [i*i*i for i in x]
nums = [1,2,3,4,5]
Thread(target = func1, args=(nums,)).start()
Thread(target = func2, args=(nums,)).start()
print list1, list2
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