如何在Python中将信息与生成器的末尾一起传递？引发StopIteration（myobj）未被捕获

Question

我发现了一种精巧的解决方案，可以解决在生成器耗尽之后返回最终信息的问题，该问题是将所需的内容放入StopIteration中。这要求在生成器函数的末尾手动引发Exception。但是，似乎无法从外部捕获。它的唯一工作方式是使用自定义异常，该异常会破坏对任何对返回值不感兴趣的人（例如，在for语句中）的生成器协议。 。

def generator():
    for i in range(3):
        print('inside', i)
        yield i
    print('raising...')
    raise StopIteration('<<Some accumulated result.>>')

p = generator()
try:
    while True:
        print('\n Trying...')
        print('outside', next(p))
except StopIteration as e:
    print('handling', e.arg

输出：

Trying...
inside 0
outside 0

Trying...
inside 1
outside 1

Trying...
inside 2
outside 2

Trying...
raising...
RuntimeError: generator raised StopIteration

预期输出：

Trying...
inside 0
outside 0

Trying...
inside 1
outside 1

Trying...
inside 2
outside 2

Trying...
raising...
handling ('<<Some accumulated result.>>')

Answer 1

实际上是生成器的返回值seems to be put inside the exception by default：

def generator():
    for i in range(3):
        print('inside', i)
        yield i
    print('raising...')
    return '<<Some accumulated result.>>'


p = generator()
try:
    while True:
        print('\n Trying...')
        print('outside', next(p))
except StopIteration as e:
    print('handling', e.args)

输出：

Trying...
inside 0
outside 0

Trying...
inside 1
outside 1

Trying...
inside 2
outside 2

Trying...
raising...
handling ('<<Some accumulated result.>>')