Python多线程原理与用法详解

import threading
def runtask(name):
  print("%s线程已启动"%name)
t = threading.Thread(target=runtask,args=("task1",))  # args因为是一个元组，所以必须这样写,否则运行将报错
t.start()

import threading
import time
def runtask(name):
  print("%s线程已启动"%name)
  time.sleep(2)
t = threading.Thread(target=runtask,args=("task1",))
t.start()
t.join()
print("abc")  # 过了2s才会打印，若无等待将看不到等待2s的效果

import threading,time
def runtask(name):
  global count
  time.sleep(1)
  lock.acquire()   # 获取锁资源，并返回是否获取成功
  count+=1
  print(name,count)
  lock.release()   # 释放资源
count = 0
lock = threading.Lock()   # 互斥锁
for index in range(50):
  t = threading.Thread(target=runtask,args=("thread%d"%index,))
  t.start()

def run1():
  global count1
  lock.acquire()
  count1 += 1
  lock.release()
  return count1
def run2():
  global count2
  lock.acquire()
  count2 += 1
  lock.release()
  return count2
def runtask():
  lock.acquire()
  r1 = run1()
  print("="*30)
  r2 = run2()
  lock.release()
  print(r1,r2)
count1,count2 = 0,0
lock = threading.Lock()
for index in range(50):
  t = threading.Thread(target=runtask,)
  t.start()

lock = threading.Lock()

lock = threading.RLock()

import time,threading
def runtask(name):
  global num
  semaphore.acquire()
  time.sleep(1)
  num += 1
  semaphore.release()
  print(name,num)
num = 0
semaphore = threading.BoundedSemaphore(5)
for index in range(50):
  t = threading.Thread(target=runtask,args=("线程%s"%index,))
  t.start()

import threading,time
def lighter():
  num = 0
  event.set()   # 设置标记
  while True:
    if num >= 5 and num < 10:
      event.clear()  # 清除标记
      print("红灯亮起，车辆禁止通行")
    if num >= 10:
      event.set()   # 设置标记
      print("绿灯亮起，车辆可以通行")
      num = 0
    num += 1
    time.sleep(1)
def car():
  while True:
    if event.is_set():
      print("车辆正在跑...")
    else:
      print("车辆停下了")
      event.wait()
    time.sleep(1)
event = threading.Event()
t1 = threading.Thread(target=lighter,)
t2 = threading.Thread(target=car,)
t1.start()
t2.start()