search
HomeBackend DevelopmentPython TutorialHow to define and call threads in Python through the threading module

Define thread

The simplest method: use target to specify the target function to be executed by the thread, and then use start() to start it.

Grammar:

class threading.Thread(group=None, target=None, name=None, args=(), kwargs={})

group is always None and is reserved for future use. target is the name of the function to be executed. name is the thread name, the default is Thread-N, usually the default can be used. However, when the server-side program thread functions are different, it is recommended to name them.

#!/usr/bin/env python3
# coding=utf-8
import threading

def function(i):
  print ("function called by thread {0}".format(i))
threads = []

for i in range(5):
  t = threading.Thread(target=function , args=(i,))
  threads.append(t)
  t.start()
  t.join()

Execution result:

$ ./threading_define.py 
function called by thread 0
function called by thread 1
function called by thread 2
function called by thread 3
function called by thread 4

Determine the current thread

#!/usr/bin/env python3
# coding=utf-8

import threading
import time

def first_function():
  print (threading.currentThread().getName()+ str(' is Starting \n'))
  time.sleep(3)
  print (threading.currentThread().getName()+ str( ' is Exiting \n'))
  
def second_function():
  print (threading.currentThread().getName()+ str(' is Starting \n'))
  time.sleep(2)
  print (threading.currentThread().getName()+ str( ' is Exiting \n'))
  
def third_function():
  print (threading.currentThread().getName()+\
  str(' is Starting \n'))
  time.sleep(1)
  print (threading.currentThread().getName()+ str( ' is Exiting \n'))
  
if __name__ == "__main__":
  t1 = threading.Thread(name='first_function', target=first_function)
  t2 = threading.Thread(name='second_function', target=second_function)
  t3 = threading.Thread(name='third_function',target=third_function)
  t1.start()
  t2.start()
  t3.start()

Execution result:

$ ./threading_name.py 
first_function is Starting 
second_function is Starting 
third_function is Starting 
third_function is Exiting 
second_function is Exiting 
first_function is Exiting

Use with logging module:

#!/usr/bin/env python3
# coding=utf-8

import logging
import threading
import time

logging.basicConfig(
  level=logging.DEBUG,
  format='[%(levelname)s] (%(threadName)-10s) %(message)s',
  )
  
def worker():
  logging.debug('Starting')
  time.sleep(2)
  logging.debug('Exiting')
  
def my_service():
  logging.debug('Starting')
  time.sleep(3)
  logging.debug('Exiting')
  
t = threading.Thread(name='my_service', target=my_service)
w = threading.Thread(name='worker', target=worker)
w2 = threading.Thread(target=worker) # use default name
w.start()
w2.start()
t.start()

Execution result:

$ ./threading_names_log.py[DEBUG] (worker  ) Starting
[DEBUG] (Thread-1 ) Starting
[DEBUG] (my_service) Starting
[DEBUG] (worker  ) Exiting
[DEBUG] (Thread-1 ) Exiting
[DEBUG] (my_service) Exiting


Use threads in subclasses

Our previous threads were all created in the form of structured programming. Threads can also be created by integrating the threading.Thread class. The Thread class first completes some basic initialization and then calls its run(). The run() method will call the target function passed to the constructor.

#!/usr/bin/env python3
# coding=utf-8

import logging
import threading
import time

exitFlag = 0

class myThread (threading.Thread):
  def __init__(self, threadID, name, counter):
    threading.Thread.__init__(self)
    self.threadID = threadID
    self.name = name
    self.counter = counter
    
  def run(self):
    print ("Starting " + self.name)
    print_time(self.name, self.counter, 5)
    print ("Exiting " + self.name)
    
def print_time(threadName, delay, counter):
  while counter:
    if exitFlag:
      thread.exit()
    time.sleep(delay)
    print ("%s: %s" %(threadName, time.ctime(time.time())))
    counter -= 1
    
# Create new threads
thread1 = myThread(1, "Thread-1", 1)
thread2 = myThread(2, "Thread-2", 2)
# Start new Threads
thread1.start()
thread2.start()
print ("Exiting Main Thread")

Execution result:

$ ./threading_subclass.py 
Starting Thread-1
Starting Thread-2
Exiting Main Thread
Thread-1: Tue Sep 15 11:03:21 2015
Thread-2: Tue Sep 15 11:03:22 2015
Thread-1: Tue Sep 15 11:03:22 2015
Thread-1: Tue Sep 15 11:03:23 2015
Thread-2: Tue Sep 15 11:03:24 2015
Thread-1: Tue Sep 15 11:03:24 2015
Thread-1: Tue Sep 15 11:03:25 2015
Exiting Thread-1
Thread-2: Tue Sep 15 11:03:26 2015
Thread-2: Tue Sep 15 11:03:28 2015
Thread-2: Tue Sep 15 11:03:30 2015
Exiting Thread-2

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Is Tuple Comprehension possible in Python? If yes, how and if not why?Is Tuple Comprehension possible in Python? If yes, how and if not why?Apr 28, 2025 pm 04:34 PM

Article discusses impossibility of tuple comprehension in Python due to syntax ambiguity. Alternatives like using tuple() with generator expressions are suggested for creating tuples efficiently.(159 characters)

What are Modules and Packages in Python?What are Modules and Packages in Python?Apr 28, 2025 pm 04:33 PM

The article explains modules and packages in Python, their differences, and usage. Modules are single files, while packages are directories with an __init__.py file, organizing related modules hierarchically.

What is docstring in Python?What is docstring in Python?Apr 28, 2025 pm 04:30 PM

Article discusses docstrings in Python, their usage, and benefits. Main issue: importance of docstrings for code documentation and accessibility.

What is a lambda function?What is a lambda function?Apr 28, 2025 pm 04:28 PM

Article discusses lambda functions, their differences from regular functions, and their utility in programming scenarios. Not all languages support them.

What is a break, continue and pass in Python?What is a break, continue and pass in Python?Apr 28, 2025 pm 04:26 PM

Article discusses break, continue, and pass in Python, explaining their roles in controlling loop execution and program flow.

What is a pass in Python?What is a pass in Python?Apr 28, 2025 pm 04:25 PM

The article discusses the 'pass' statement in Python, a null operation used as a placeholder in code structures like functions and classes, allowing for future implementation without syntax errors.

Can we Pass a function as an argument in Python?Can we Pass a function as an argument in Python?Apr 28, 2025 pm 04:23 PM

Article discusses passing functions as arguments in Python, highlighting benefits like modularity and use cases such as sorting and decorators.

What is the difference between / and // in Python?What is the difference between / and // in Python?Apr 28, 2025 pm 04:21 PM

Article discusses / and // operators in Python: / for true division, // for floor division. Main issue is understanding their differences and use cases.Character count: 158

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

PhpStorm Mac version

PhpStorm Mac version

The latest (2018.2.1) professional PHP integrated development tool

SecLists

SecLists

SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!