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  • 线程

    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
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  • 原文地址:https://www.cnblogs.com/xuguangzong/p/8422805.html
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