python线程中的全局变量与局部变量

在python多线程开发中，全局变量是多个线程共享的数据，局部变量是各自线程的，非共享的。

如下几种写法都是可以的：

第一种：将列表当成参数传递给线程

from threading import Thread

import time

def work1(nums):

    nums.append(44)

    print("----in work1---",nums)

def work2(nums):

    #延时一会，保证t1线程中的事情做完

    time.sleep(1)

    print("----in work2---",nums)

if __name__=='__main__':

    g_nums = [11, 22, 33]

    t1 = Thread(target=work1, args=(g_nums,)) #这种写法是将列表当成参数传递

    t1.start()

    t2 = Thread(target=work2, args=(g_nums,))

    t2.start()

第二种：不传递，直接用

from threading import Thread

import time

def work1():

    nums.append(44)

    print("----in work1---",nums)

def work2():

    #延时一会，保证t1线程中的事情做完

    time.sleep(1)

    print("----in work2---",nums)

if __name__=='__main__':

    nums = [11, 22, 33]

    t1 = Thread(target=work1)

    t1.start()

    t2 = Thread(target=work2)

    t2.start()

结果都一样：

对于参数是字符串，数字这种不可变类型的变量

，改变变量的值的时候，要用上global，否则程序报错。

from threading import Thread

import time

def work1():

    global nums

    nums+1

    print("----in work1---",nums)

def work2():

    #延时一会，保证t1线程中的事情做完

    time.sleep(1)

    print("----in work2---",nums)

if __name__=='__main__':

    nums = 12

    t1 = Thread(target=work1)

    t1.start()

    t2 = Thread(target=work2)

    t2.start()

结果：

from threading import Thread

import time

def work1(nums):

    nums=nums+1

    print("----in work1---",nums)

def work2(nums):

    #延时一会，保证t1线程中的事情做完

    time.sleep(1)

    print("----in work2---",nums)

if __name__=='__main__':

    g_nums = 11

    t1 = Thread(target=work1, args=(g_nums,))

    t1.start()

    t2 = Thread(target=work2, args=(g_nums,))

    t2.start()

结果：

from threading import Thread

import time

def work1(nums):

    nums+1

    print("----in work1---",nums)

def work2(nums):

    #延时一会，保证t1线程中的事情做完

    time.sleep(1)

    print("----in work2---",nums)

if __name__=='__main__':

    g_nums = 11

    t1 = Thread(target=work1, args=(g_nums,))

    t1.start()

    t2 = Thread(target=work2, args=(g_nums,))

    t2.start()

结果：

python线程中的全局变量与局部变量的相关教程结束。