进程是执行中的程序,线程则是轻量级的进程
线程是cpu调度的最小单位,而进程是资源分配的最小单位
进程包含线程,GIL全局解释器锁,只是在Cpython中,
在一个程序中可以同时有多进程和线程
开启多线程
import os import time from threading import Thread class Tt(Thread): def run(self): time.sleep(1) print('nihao ',os.getpid()) for i in range(10): t = Tt() t.start()
C:UsershcAppDataLocalProgramsPythonPython36python3.exe C:/s9/37day/37.py nihao 12076 nihao 12076 nihao 12076 nihao 12076 nihao 12076 nihao 12076 nihao 12076 nihao 12076 nihao 12076 nihao 12076 Process finished with exit code 0
开启多线程的另一种方法
import time from threading import Thread class A(Thread): count=0 def run(self):这里需要注意的是这个函数名必须是run A.count+=1 time.sleep(1) print('nihao ') for i in range(10): t = A() t.start() print(t.count)
C:UsershcAppDataLocalProgramsPythonPython36python3.exe C:/s9/38day/39.py 10 nihao nihao nihao nihao nihao nihao nihao nihao nihao nihao Process finished with exit code 0
真实的线程数要加1
计算线程数
import threading import time def run(i): time.sleep(2) print(i,threading.currentThread().name,threading.currentThread().ident) for i in range(10): t = threading.Thread(target=run,args=(i,)) t.start() print(threading.active_count())
C:UsershcAppDataLocalProgramsPythonPython36python3.exe C:/s9/38day/39.py 11 1 Thread-2 7068 0 Thread-1 9276 2 Thread-3 12568 8 Thread-9 8620 7 Thread-8 12560 6 Thread-7 4976 3 Thread-4 11940 9 Thread-10 5768 4 Thread-5 12500 5 Thread-6 9932 Process finished with exit code 0