Are nested try/except blocks in python a good programming practice?

Question

I\'m writing my own container, which needs to give access to a dictionary inside by attribute calls. The typical use of the container would be like this:

dic         


        

Answer 1

One thing I like to avoid is raising a new exception while handling an old one. It makes the error messages confusing to read.

For example, in my code, I originally wrote

try:
    return tuple.__getitem__(self, i)(key)
except IndexError:
    raise KeyError(key)

And I got this message.

>>> During handling of above exception, another exception occurred.

What I wanted was this:

try:
    return tuple.__getitem__(self, i)(key)
except IndexError:
    pass
raise KeyError(key)

It doesn't affect how exceptions are handled. In either block of code, a KeyError would have been caught. This is merely an issue of getting style points.