多线程

import threadingdef main():print(threading.active_count())print(threading.enumerate())print(threading.current_thread())if __name__ == '__main__':main()D:\PythonTest>python test.py
1
[<_MainThread(MainThread, started 4124)>]
<_MainThread(MainThread, started 4124)>

线程数
print(threading.active_count())线程名
print(threading.enumerate())当前线程数
print(threading.current_thread())添加线程
added_thread = threading.Thread()
added_thread.start()

添加线程add thread

import threadingdef thread_job():print("This is an added Thread,number is %s"% threading.current_thread())def main():added_thread = threading.Thread(target =thread_job)added_thread.start()if __name__ == '__main__':main()

import threading
import timedef thread_job():print('T1 start\n')for i in range(10):time.sleep(0.1)print('T1 finish\n')def main():added_thread = threading.Thread(target =thread_job,name = 'T1')added_thread.start()print('all done\n')if __name__ == '__main__':main()D:\PythonTest>python test.py
T1 startall doneT1 finish

join功能

等待
added_thread.join()

import threading
import timedef thread_job():print('T1 start\n')for i in range(10):time.sleep(0.1)print('T1 finish\n')def main():added_thread = threading.Thread(target =thread_job,name = 'T1')added_thread.start()added_thread.join()print('all done\n')if __name__ == '__main__':main()D:\PythonTest>python test.py
T1 startT1 finishall done

• 比较

import threading
import timedef thread_job():print('T1 start\n')for i in range(10):time.sleep(0.1)print('T1 finish\n')def T2_job():print('T2 start\n')print('T2 finish\n')def main():added_thread = threading.Thread(target = thread_job,name = 'T1')thread2 = threading.Thread(target =T2_job,name = 'T2')added_thread.start()thread2.start()print('all done\n')if __name__ == '__main__':main()D:\PythonTest>python test.py
T1 startT2 startT2 finishall doneT1 finish

import threading
import timedef thread_job():print('T1 start\n')for i in range(10):time.sleep(0.1)print('T1 finish\n')def T2_job():print('T2 start\n')print('T2 finish\n')def main():added_thread = threading.Thread(target = thread_job,name = 'T1')thread2 = threading.Thread(target =T2_job,name = 'T2')added_thread.start()thread2.start()added_thread.join()print('all done\n')if __name__ == '__main__':main()D:\PythonTest>python test.py
T1 startT2 startT2 finishT1 finishall done

import threading
import timedef thread_job():print('T1 start\n')for i in range(10):time.sleep(0.1)print('T1 finish\n')def T2_job():print('T2 start\n')print('T2 finish\n')def main():added_thread = threading.Thread(target = thread_job,name = 'T1')thread2 = threading.Thread(target =T2_job,name = 'T2')added_thread.start()thread2.start()thread2.join()print('all done\n')if __name__ == '__main__':main()D:\PythonTest>python test.py
T1 startT2 startT2 finishall doneT1 finish

queue功能

import threading
import time
from queue import Queuedef job(l,q):for i in range(len(l)):l[i] = l[i] ** 2q.put(l)def multithreading():q = Queue()threads = []data = [[1,2,3],[3,4,5],[4,4,4],[5,5,5]]for i in range(4):t = threading.Thread(target = job,args = (data[i],q))t.start()threads.append(t)for thread in threads:thread.joinresults = []for _ in range(4):results.append(q.get())print(results)if __name__ == '__main__':multithreading()

GIL

import threading
import time
from queue import Queue
import copydef job(l,q):res = sum(l)q.put(res)def multithreading(l):q = Queue()threads = []for i in range(4):t = threading.Thread(target = job,args = (copy.copy(l),q),name = 'T%i'%i)t.start()threads.append(t)[t.join() for t in threads]total = 0for _ in range(4):total += q.get()print(total)def normal(l):total = sum(l)print(total)if __name__ == '__main__':l = list(range(1000000))s_t = time.time()normal(l * 4)print('normal:',time.time() - s_t)s_t = time.time()multithreading(l)print('multithreading:',time.time() - s_t)D:\PythonTest>python test.py
1999998000000
normal: 0.13805341720581055
1999998000000
multithreading: 0.16271591186523438

锁loop

import threading
import time
from queue import Queuedef job1():global Afor i in range(10):A += 1print('join1',A)def job2():global Afor i in range(10):A += 10print('join2',A)if __name__ == '__main__':A = 0t1 = threading.Thread(target = job1)t2 = threading.Thread(target = job2)t1.start()t2.start()t1.join()t2.join()D:\PythonTest>python test.py
join1 1
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join2 12
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join2 110

import threading
import time
from queue import Queuedef job1():global A,locklock.acquire()for i in range(10):A += 1print('join1',A)lock.release()def job2():global A,locklock.acquire()for i in range(10):A += 10print('join2',A)lock.release()if __name__ == '__main__':lock = threading.Lock()A = 0t1 = threading.Thread(target = job1)t2 = threading.Thread(target = job2)t1.start()t2.start()t1.join()t2.join()D:\PythonTest>python test.py
join1 1
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