python - threading

线程的使用书写示例：
（1）
import threading
import time

def run(str1):
    print("task:", str1)
    time.sleep(5)

for i in range (30):
    t1 = threading.Thread(target= run ,args=("abc",))
    t2 = threading.Thread(target= run ,args=("cdef",))

    t1.start()
    t2.start()

（2）

import threading
import time

def run(str1):
    print("task:", str1)
    time.sleep(5)
　　 print("task done :",str1)
start_time=time.time()
for i in range (300):
    t1 = threading.Thread(target= run ,args=("str_%s"%i,))
    t1.start()

print("cost:",time.time()-start_time)#cost: 0.03604459762573242

（3）

import  threading
import time
class MyThreading(threading.Thread ):
    def __init__(self,name):
        super(MyThreading,self).__init__()
        self.name = name
    def run(self): #必须要写成run函数
        print("姓名：",self.name)
        time.sleep(5)
t1 = MyThreading("张三")
t2 = MyThreading("李四")
t1.start()
t2.start()

（4）

import  threading
import time
class MyThreading(threading.Thread ):
    def __init__(self,name,sleep_time):
        super(MyThreading,self).__init__()
        self.name = name
        self.sleep_time=sleep_time
    def run(self):
        print("姓名：",self.name)
        time.sleep(self.sleep_time)
        print("task done...",self.name)
t1 = MyThreading("张三",2)
t2 = MyThreading("李四",4)
t1.start()
t2.start()
t1.join()
print("main threading ......")

"""
result:
        姓名： 张三
        姓名： 李四
        task done... 张三
        main threading ......
        task done... 李四
"""

守护线程：

import time
def run(str1):
    print("task:", str1)
    time.sleep(5)
    print("task done :", str1)
start_time=time.time()
for i in range (300):
    t1 = threading.Thread(target= run ,args=("str_%s"%i,))
    t1.setDaemon(True)           #守护线程
    t1.start()
print("-------------task has finished-------------")
print("cost:",time.time()-start_time)#cost: 0.03604459762573242

线程锁示例（Python3以上不须用线程锁）

import threading
num = 0
lock=threading.Lock()
def run():
    lock.acquire()
    global num
    num += 1
    lock.release()
for i in  range(100):
    t=threading.Thread(target=run)
    t.start()
print("num:",num)