Python线程（一）

优化之前的代码：
from multiprocessing.dummy import  Pool as ThreadPool
from datetime import datetime
import time


def geEntry(a,b):
    time.sleep(2)
    now = datetime.now() 
    print(now)
    return now

pool = ThreadPool(8)
now = datetime.now()                                          
a=list(range(10))
print(a)
# entries=pool.map(self.geEntry, plan_obj.entries)
entries=[]
b=1
c=2
for i in a:            
    result=pool.apply_async(geEntry, args=(b,c))    
    entries.append(result.get())                 
pool.close()
pool.join() 

Output:
0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2020-07-12 20:12:51.402016
2020-07-12 20:12:53.403585
2020-07-12 20:12:55.404262
2020-07-12 20:12:57.405886
2020-07-12 20:12:59.406552
2020-07-12 20:13:01.407239
2020-07-12 20:13:03.407955
2020-07-12 20:13:05.409428
2020-07-12 20:13:07.410663
2020-07-12 20:13:09.412293

优化后的代码:

from multiprocessing.dummy import  Pool as ThreadPool
from datetime import datetime
import time


def geEntry(a,b):
    time.sleep(2)
    now = datetime.now() 
    print(now)
    return now

pool = ThreadPool(8)
now = datetime.now()                                          
a=list(range(10))
print(a)
# entries=pool.map(self.geEntry, plan_obj.entries)
entries=[]
b=1
c=2
for i in a:            
    result=pool.apply_async(geEntry, args=(b,c))    
    entries.append(result)   #需要把result先放到list里，如果直接用result.get()会变成同步按顺序调用，多线程同时指向失效              
pool.close()
pool.join() 

for result in entries:
    print("** %s" % result.get())

output:
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
2020-07-12 20:06:57.046435
2020-07-12 20:06:57.046496
2020-07-12 20:06:57.046496
2020-07-12 20:06:57.046496
2020-07-12 20:06:57.046496
2020-07-12 20:06:57.046496
2020-07-12 20:06:57.046496
2020-07-12 20:06:57.046496
2020-07-12 20:06:59.047407
2020-07-12 20:06:59.047407
** 2020-07-12 20:06:57.046496
** 2020-07-12 20:06:57.046496
** 2020-07-12 20:06:57.046496
** 2020-07-12 20:06:57.046496
** 2020-07-12 20:06:57.046496
** 2020-07-12 20:06:57.046435
** 2020-07-12 20:06:57.046496
** 2020-07-12 20:06:57.046496
** 2020-07-12 20:06:59.047407
** 2020-07-12 20:06:59.047407