问题描述
for i in MyClass():
if i == 'some condition':
break
# do other stuff
我需要能够处理早期终止迭代的时间。可以在类实现中实现吗?
解决方法
您可以尝试捕获GeneratorExit
:
class A:
def __iter__(self):
# You need to adapt this to your actual __iter__ implementation:
i = 0
try:
while i < 5:
yield i
i += 1
except GeneratorExit:
print("GeneratorExit")
如果您不存储发生器,例如在
# If you break in any of these two loops,you'll get GeneratorExit printed:
a = A()
for i in a: ...
for i in A(): ...
如果存储了生成器,则只有在生成器被垃圾回收而不用尽的情况下,您才会获得GeneratorExit
:
a = A()
it = iter(a)
for i in it:
if i == 2:
break # Does not print GeneratorExit.
it = iter(a) # Prints GeneratorExit.
无论如何,如果生成器仍然存在,您可能不想清理,否则会变得很奇怪:
it = iter(A())
for i in it:
if i == 2:
break
for i in it: # What happens here if you cleaned-up?
pass