我认为以下代码可以表达所需的结果:
class LockIterator(object):
def __init__(self, lock_list):
self.lock_list = lock_list
def __iter__(self):
return self
def __next__(self):
for resource in self.lock_list:
print( "Locking N resources" )
yield resource
print( "Unlocking N resources" )
print( "Unlocking remaining resources" )
raise StopIteration
for item in LockIterator( ["Resource 1", "Resource 2", "Resource 3"] ):
print("Safe resource usage:", item)
但是,在Python上运行它,我得到了一个无限循环:
Safe resource usage: <generator object LockIterator.__next__ at 0x000001A8BDA24938>
Safe resource usage: <generator object LockIterator.__next__ at 0x000001A8BB8AEE60>
Safe resource usage: <generator object LockIterator.__next__ at 0x000001A8BDA24938>
Safe resource usage: <generator object LockIterator.__next__ at 0x000001A8BB8AEE60>
Safe resource usage: <generator object LockIterator.__next__ at 0x000001A8BDA24938>
Safe resource usage: <generator object LockIterator.__next__ at 0x000001A8BB8AEE60>
Safe resource usage: <generator object LockIterator.__next__ at 0x000001A8BDA24938>
Safe resource usage: <generator object LockIterator.__next__ at 0x000001A8BB8AEE60>
...
在我的想象中,它应该像这样运行:
Locking N resources
Safe resource usage: Resource 1
Unlocking N resources
Locking N resources
Safe resource usage: Resource 2
Unlocking N resources
Locking N resources
Safe resource usage: Resource 3
Unlocking N resources
Unlocking remaining resources
您知道如何在普通的for循环中自动强制这种行为吗?
for item in LockIterator( ["Resource 1", "Resource 2", "Resource 3"] ):
print("Safe resource usage:", item)
答案 0 :(得分:1)
__next__
。由于您的__next__
是生成器,因此每次都会返回。
相反,您可以摆脱该类,而只需编写一个生成器:
def LockIterator(lock_list):
# better name this lockify or something else in snake_case
for resource in lock_list:
print("Locking N resources")
yield resource
print("Unlocking N resources")
print("Unlocking remaining resources")
答案 1 :(得分:1)
我还设法通过删除__next__
并将其主体移至__iter__
方法来对其进行修复:
class LockIterator(object):
def __init__(self, lock_list):
self.lock_list = lock_list
def __iter__(self):
for resource in self.lock_list:
print( "Locking N resources" )
yield resource
print( "Unlocking N resources" )
print( "Unlocking remaining resources" )
for item in LockIterator( ["Resource 1", "Resource 2", "Resource 3"] ):
print("Safe resource usage:", item)