Python threading active_count()用法及代码示例

Python threading.active_count() 方法

active_count() 是 Python 中线程模块的内置方法。它用于返回任何时刻处于活动状态的 Thread 对象的数量。

模块：

    import threading

用法:

    active_count()

参数：

• None

返回值：

这个方法的返回类型是<class 'int'>，它返回任何时刻的活动线程类对象的数量。

例：

# Python program to explain the use of 
# active_count() method in Threading Module

import time
import threading

def thread_1(i):
    time.sleep(2)
    print("Number of active threads:", threading.active_count())
    print('Value by Thread 1:', i)

def thread_2(i):
    time.sleep(5)
    print("Number of active threads:", threading.active_count())
    print('Value by Thread 2:', i)
    
def thread_3(i):
    print("Number of active threads:", threading.active_count())
    print("Value by Thread 3:", i)
    
# Creating sample threads 
thread1 = threading.Thread(target=thread_1, args=(1,))
thread2 = threading.Thread(target=thread_2, args=(2,))
thread3 = threading.Thread(target=thread_3, args=(3,))

print("Number of active threads in the starting:", threading.active_count())
print("The active threads in the starting is 1 which is the main thread that executes till the program runs")

# Starting the threads
thread1.start()
thread2.start()
thread3.start()

输出

Number of active threads in the starting:1
The active threads in the starting is 1 which is the main thread that executes till the program runs
Number of active threads:4
Value by Thread 3:3
Number of active threads:3
Value by Thread 1:1
Number of active threads:2
Value by Thread 2:2