Question

我正在尝试编写一个简单的线程程序。当我不尝试将任何变量传递给目标函数时，它会很好地工作。

import threading
import time
import datetime

def my_function():
    thread_start_time = str(datetime.datetime.now())
    thread_start_time_remove_microseconds = thread_start_time[:19]

    print("\n\nThread Execution Start Time: ", thread_start_time_remove_microseconds)
    print("I am being printed by mythread. Sleeping for 5 seconds. Main thread will wait till I finish")
    time.sleep(5)

    thread_end_time = str(datetime.datetime.now())
    thread_end_time_remove_microseconds = thread_end_time[:19]

    print("Thread Execution End Time: ", thread_end_time_remove_microseconds)


def main():
    mythread= threading.Thread(target=my_function, name="thread1")
    mythread.start()

    print("\n\n","=" * 31,"I am printed by the main thread","=" * 31,"\n\n")


if __name__ == "__main__":
    main()

结果为：

Thread Execution Start Time: 

 2018-09-09 17:02:46
 =============================== I am printed by the main thread =============================== 


I am being printed by mythread. Sleeping for 5 seconds. Main thread will wait till I finish
Thread Execution End Time:  2018-09-09 17:02:51

Process finished with exit code 0

但是，当我尝试将变量传递给函数时，出现以下错误：导入线程导入时间导入日期时间

def my_function(one_variable):
    print(one_variable)
    thread_start_time = str(datetime.datetime.now())
    thread_start_time_remove_microseconds = thread_start_time[:19]

    print("\n\nThread Execution Start Time: ", thread_start_time_remove_microseconds)
    print("I am being printed by mythread. Sleeping for 5 seconds. Main thread will wait till I finish")
    time.sleep(5)

    thread_end_time = str(datetime.datetime.now())
    thread_end_time_remove_microseconds = thread_end_time[:19]

    print("Thread Execution End Time: ", thread_end_time_remove_microseconds)


def main():
    mythread= threading.Thread(target=my_function, name="thread1", args=("This is one variable from main"))
    mythread.start()

    print("\n\n","=" * 31,"I am printed by the main thread","=" * 31,"\n\n")


if __name__ == "__main__":
    main()

结果为：

=============================== I am printed by the main thread =============================== 


Exception in thread thread1:
Traceback (most recent call last):
  File "C:\Users\dparvez\AppData\Local\Programs\Python\Python36-32\lib\threading.py", line 916, in _bootstrap_inner
    self.run()
  File "C:\Users\dparvez\AppData\Local\Programs\Python\Python36-32\lib\threading.py", line 864, in run
    self._target(*self._args, **self._kwargs)
TypeError: my_function() takes 1 positional argument but 30 were given


Process finished with exit code 0

有人可以帮忙，为什么我会收到此错误消息。

Answer 1

您需要用逗号将args变成元组，如下所示：

mythread= threading.Thread(
    target=my_function
    name="thread1",
    args=("This is one variable from main",))

这是因为threading.Thread（）期望args可以可迭代，并对其进行枚举以使所有args传递给函数。

表达式（“ string”）等于“ string”-并且它是可迭代的，导致（“ s”，“ t”，“ r”，“ i”，“ n”，“ g” ）。不是您想要的。要告诉Python（“ string”）是一个单元素元组而不是带括号的表达式，请执行（“ string”，）。

将参数传递给Python线程时发生TypeError

1 个答案: