如何从 try catch 块内部中断 for 循环？

Question

我正在尝试找到一种方法来摆脱这个 for 循环如果 try except 块内的代码块（for 循环内）成功执行，并且没有调用异常。

这是对我不起作用的代码：

attempts = ['I15', 'J15']
for attempt in attempts:
    try:
        avar = afunc(attempt)
        break
    except KeyError:
        pass
        if attempt == attempts[-1]:
            raise KeyError

因为在I15执行成功后还在调用attempts列表中的J15项

代码在这里：

    except KeyError:
        pass
        if attempt == attempts[-1]:
            raise KeyError

如果代码已经在attempts

中尝试了整个attempt，则用于抛出实际的异常

Answer 1

我相信最干净的方法是 continue 在 except 块内，然后 breaking 就在它后面。在这种情况下，您甚至不必使用 avar（除非我误解了问题）。

attempts = ['I15', 'J15']
for attempt in attempts:
    try:
        afunc(attempt)
    except KeyError:
        continue
    break

如果您以后确实需要 avar：

attempts = ['I15', 'J15']
for attempt in attempts:
    try:
        avar = afunc(attempt)
    except KeyError:
        continue
    break
print(avar) # avar is a available here, as long as at least one attempt was successful

Answer 2

您需要 for … else 概念：https://docs.python.org/3/tutorial/controlflow.html#break-and-continue-statements-and-else-clauses-on-loops

attempts = ['I15', 'J15']
for attempt in attempts:
    try:
        avar = afunc(attempt)
    except KeyError:
        # error, let's try another item from attempts
        continue
    else:
        # success, let's get out of the loop
        break
else:
    # this happens at the end of the loop if there is no break
    raise KeyError

如何从 try catch 块内部中断 for 循环？

How to break for loop from inside of its try catch block?

python

for-loop

python-2.7

python-3.x

try-except