Two ways to turn on threads,

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Catalogue
1, two ways to turn on threading * * * * *
2, the difference between threads and processes * * *
3, other methods and properties of the thread object
4, Daemon thread
5, Mutual exclusion lock
6, deadlock phenomenon with pass-through lock
7, Signal volume
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#1 two ways to turn on threads
Import time
From threading Import Thread


def dask (name):
Print ('%s is running '%name)
Time.sleep (1)
Print ('%s is do '%name)


T=thread (target=dask,args= (' Egon ',))
T.start ()
Print (' master ')

# The Second Kind
Class Mythread (Thread):
def __init__ (self,name):
Super (Mythread, self). __init__ ()
Self.name=name

def run (self):
Print ("%s is running"%self.name)

Print ('%s is do '%self.name)


T=mythread (' Alex ')
T.start ()
Print (' master ')

#--------------------Process vs thread vs difference--------------------
#1, the thread is open fast, the thread executes the code no longer survives
# All non-daemons will die after the main thread executes, because the main process is going back to the operating system to receive resources
# If the child thread is not finished, the child thread cannot find the data

From threading Import Thread
From multiprocessing import Process
Import time

def task (name):
Print ('%s is running '%name)
Time.sleep (2)
Print ('%s is do '%name)

if __name__ = = ' __main__ ':
T=thread (target=task,args= (' Child Threads ',))
T.start ()
Print (' master ')


#2. Multiple threads under the same process share data within the process, and child threads can modify the data within that process to be called by other child threads
#子进程修改全局变量修改的只是自己的, the child process cannot modify the resources of the parent process because the space is physically isolated
From threading Import Thread
Import time
x=100
Def dask ():
Global X
x=88
Print (x)
Time.sleep (1)


#开启多个子进程多个子进程的PID are different, open multiple sub-threads, multiple child threads and the main thread of the PID are consistent

T=thread (Target=dask)
T.start ()
T.join () #会等子线程运行完毕才往下走
Print (' main ', X)

#查看pid
From threading Import Thread
Import Os,time

Def task ():
Print (Os.getpid ())

T=thread (Target=task)
T.start ()
Print (' Master ', Os.getpid ())

# ====================== Other methods and properties of thread objects ==================#
#主进程等子进程是因为主进程要给子进程收尸
#进程必须等待其内部所有线程都隐形完毕才结束
From threading Import Current_thread,active_count,enumerate
Import time

def task (name):
Print ('%s is running '%name)
Time.sleep (2)
Print ('%s is do '%name)

T=thread (target=task,args= (' Child Threads ',))
T.start ()
Print (' master ')


# ------------------------------------------
Def task ():
Print ('%s is running '%current_thread (). Name)
Time.sleep (2)
Print ('%s is done '%current_thread (). Name)#查看当前进程的名字

Print (' walk up here ')
T=thread (target=task,name= ' xxx ')
T.start ()
T.join ()
Print (T.is_alive ()) #判断进/thread is alive
Print (T.getname ()) #拿到线程对象的名字xxx
Print (Enumerate ())

Current_thread (). SetName (' main thread ')
Print (' Master ', Current_thread (). Name) #拿到当前线程的名字

# Methods for thread instance objects
# isAlive (): Returns whether the thread is active. 
# getName (): Returns the thread name. 
# SetName (): Sets the thread name. 

# Some of the methods provided by the threading module:
# Threading.currentthread (): Returns the current thread variable. 
# threading.enumerate (): Returns a list that contains the running thread. Running refers to threads that do not include pre-and post-termination threads until after the thread has started and ends. 
# Threading.activecount (): Returns the number of running threads with the same result as Len (Threading.enumerate ()). 

Two ways to turn on threads,