python之threading模块

1、threading简介

 

2、创建线程

2.1、创建2个线程

import threading

def run(n):
    print("task", n)

t1 = threading.Thread(target=run, args=("t1",))
t2 = threading.Thread(target=run, args=("t2",))

t1.start()
t2.start()

2.2、创建多个线程

import threading
import time


def run(n):
    print("task", n)
    time.sleep(2)
    print("task done", n)

start_time = time.time()

t_objs = []  # 存线程实例
for i in range(50):
    t = threading.Thread(target=run, args=("t-%s" % i,))
    t.start()
    t_objs.append(t)  # 为了不阻塞后面线程的启动，不在这里join，先放到一个列表里

for t in t_objs:  # 循环线程实例列表，等待所有线程执行完毕

    t.join()
    print("active count:",threading.activeCount())

print("----------all threads has finished...", threading.active_count())
# print("----------all threads has finished...", threading.activeCount())

2.3、使用线程锁

import threading
import time

def run(n):
    lock.acquire()
    global  num
    num +=1
    lock.release()


lock = threading.Lock()
num = 0
t_objs = [] #存线程实例
for i in range(10000):
    t = threading.Thread(target=run,args=("t-%s" %i ,))
    t.start()
    t_objs.append(t) #为了不阻塞后面线程的启动，不在这里join，先放到一个列表里

for t in t_objs: #循环线程实例列表，等待所有线程执行完毕
    t.join()

print("----------all threads has finished...",threading.current_thread(),threading.active_count())

print("num:",num)