使用字典调用python多处理映射函数
我可以使用imap执行以下操作: 但是,如果我想通过口述,可以这样做:使用字典调用python多处理映射函数,python,python-multiprocessing,python-multithreading,Python,Python Multiprocessing,Python Multithreading,我可以使用imap执行以下操作: 但是,如果我想通过口述,可以这样做: import multiprocessing def function(name, a): print("{}'s number squared:".format(name)) return a**2 b = dict(bob=1, dave=2, stan=3) pool = multiprocessing.Pool(processes=4) vals = pool.imap(function, b)
import multiprocessing
def function(name, a):
print("{}'s number squared:".format(name))
return a**2
b = dict(bob=1, dave=2, stan=3)
pool = multiprocessing.Pool(processes=4)
vals = pool.imap(function, b)
for i in vals:
print(i)
您不能传递字典,但可以传递字典列表,如下所示:
import multiprocessing
def function(input_dictionary):
print("{}'s number squared:".format(input_dictionary['name']))
return input_dictionary['number']**2
b = [ {'name' : 'bob', 'number' : 1},
{'name' : 'dave', 'number' : 2},
{'name' : 'stan', 'number' : 3}, ]
pool = multiprocessing.Pool(processes=4)
vals = pool.imap(function, b)
for i in vals:
print(i)
您可以传递字典,但字典上的映射操作仅提供字典键。如果需要字典中的项目,请使用dict.items,例如:
import multiprocessing
def function(item):
name, a = item
print("{}'s number squared:".format(name))
return a**2
if __name__ == '__main__': # you must guard your multiprocessing calls!
b = dict(bob=1, dave=2, stan=3)
with multiprocessing.Pool(processes=4) as pool:
vals = pool.imap(function, list(b.items()))
for i in vals:
print(i)
或者,如果希望相同的函数签名起作用,可以使用imap:
import multiprocessing
def function(name, a):
print("{}'s number squared:".format(name))
return a**2
if __name__ == '__main__': # you must guard your multiprocessing calls!
b = dict(bob=1, dave=2, stan=3)
with multiprocessing.Pool(processes=4) as pool:
vals = pool.starmap(function, list(b.items()))
for i in vals:
print(i)
另一种方法是使用全局变量,并将dict直接传递给pool.map,尽管它可能有点难看:
import multiprocessing
def function(name):
a = b[name]
print("{}'s number squared:".format(name))
return a**2
b = dict(bob=1, dave=2, stan=3)
if __name__ == '__main__': # you must guard your multiprocessing calls!
with multiprocessing.Pool(processes=4) as pool:
vals = pool.imap(function, b)
for i in vals:
print(i)
注意,我使用muliprocessing.Pool作为上下文管理器,因此当您离开with块时,无论发生什么情况,池都将保证关闭。这是一种最佳做法
import multiprocessing
def function(name):
a = b[name]
print("{}'s number squared:".format(name))
return a**2
b = dict(bob=1, dave=2, stan=3)
if __name__ == '__main__': # you must guard your multiprocessing calls!
with multiprocessing.Pool(processes=4) as pool:
vals = pool.imap(function, b)
for i in vals:
print(i)