Python中的線程化，需要幫助，使程序等待根據另一個函數的條件

Question

我想在Python中使用線程的東西。這是我第一次使用線程。所以任何幫助，將不勝感激。

所以這裏是事情。我開始10個線程在另一個函數中執行某些操作。但是如果在其他函數中遇到了一些條件，我應該可以在所有這些線程上調用join（）。所以我需要找到一種方法將線程對象傳遞給其他函數。有人可以幫助我找到一個方法。

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

線程可以通過使用全局變量master_wish從目標函數返回退出確實在下面的例子中招：

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()