python 中的线程，需要帮助使程序根据另一个函数的条件等待

Question

我正在 python 尝试使用线程。这是我第一次使用线程。因此，我们将不胜感激。

事情是这样的。我正在启动 10 个线程以在另一个函数中执行某些操作。但是如果在另一个函数中满足某些条件，我应该能够在所有这些线程上调用 join() 。所以我需要找到一种方法将线程对象传递给另一个函数。有人可以帮我找到解决这个问题的方法吗？

def db_routine():
#global t1, t2, t3, t4, t5, t6, t7, t8, t9, t0
connection = pymysql.connect(user='root', password='', host='127.0.0.1', database='franchisedb')
try:
    with connection.cursor() as cursor:
        sql = "select number, url, address, flag from `colleges_com`"
        cursor.execute(sql)
        #connection.commit()
        row=cursor.fetchone()
        while row is not None:
            if row[3] == 1:
                print("Item already processed.")
                row = cursor.fetchone()
                continue
            if row[2] != None:
                print("Address exists for the entry number: " + str(row[0]))
                row = cursor.fetchone()
            else:
                print("Adding address for the entry number: " + str(row[0]))
                time.sleep(.5)
                if row[0]%10 == 1:
                    t1 = threading.Thread(target=goto_url, args = (row[0], row[1]))
                    time.sleep(2)
                    t1.start()
                    row = cursor.fetchone()
                elif row[0]%10 == 2:
                    t2 = threading.Thread(target=goto_url, args = (row[0], row[1]))
                    time.sleep(2)
                    t2.start()
                    row = cursor.fetchone()
                elif row[0]%10 == 3:
                    t3 = threading.Thread(target=goto_url, args = (row[0], row[1]))
                    time.sleep(2)
                    t3.start()
                    row = cursor.fetchone()
                elif row[0]%10 == 4:
                    t4 = threading.Thread(target=goto_url, args = (row[0], row[1]))
                    time.sleep(2)
                    t4.start()
                    row = cursor.fetchone()
                elif row[0]%10 == 5:
                    t5 = threading.Thread(target=goto_url, args = (row[0], row[1]))
                    time.sleep(2)
                    t5.start()
                    row = cursor.fetchone()
                elif row[0]%10 == 6:
                    t6 = threading.Thread(target=goto_url, args = (row[0], row[1]))
                    time.sleep(2)
                    t6.start()
                    row = cursor.fetchone()
                elif row[0]%10 == 7:
                    t7 = threading.Thread(target=goto_url, args = (row[0], row[1]))
                    time.sleep(2)
                    t7.start()
                    row = cursor.fetchone()
                elif row[0]%10 == 8:
                    t8 = threading.Thread(target=goto_url, args = (row[0], row[1]))
                    time.sleep(2)
                    t8.start()
                    row = cursor.fetchone()
                elif row[0]%10 == 9:
                    t9 = threading.Thread(target=goto_url, args = (row[0], row[1]))
                    time.sleep(2)
                    t9.start()
                    row = cursor.fetchone()
                elif row[0]%10 == 0:
                    t0 = threading.Thread(target=goto_url, args = (row[0], row[1]))
                    time.sleep(2)
                    t0.start()
                    row = cursor.fetchone()
finally:
    connection.close()
    cursor.close()

Answer 1

可以通过使用全局变量从目标函数返回来退出线程master_wish在以下示例中实现了这个技巧：

import threading
import time

master_wish = True # global variable


def kill_all_demons(demon):
    while True:
        print "killing %s\n" % demon
        if not master_wish:
            return

def van_helsing():
    print "Yes Master your wish is my command"
    t1 = threading.Thread(target=kill_all_demons, args=('Dracula',))
    t2 = threading.Thread(target=kill_all_demons, args=('Wolf',))
    t1.start()
    t2.start()


def other_func():
    global master_wish
    master_wish = False
    print("good will prevail over evil")


van_helsing()
time.sleep(10)
other_func()

python 中的线程，需要帮助使程序根据另一个函数的条件等待

Threading in python, need help to make the program wait based on a condition on another function

python

multithreading

python-multithreading