Python：在 except 块中引发另一个异常以稍后捕获

Question

I want something like this:

trigger = True
try:
    x = my_function()  # This can raise IndexError
    if x is None:
        raise ValueError
except IndexError:
    trigger = False
    raise ValueError
except ValueError:
    do_something()

I want trigger to be False when IndexError is raised, and do_something() to happen both if IndexError is raised, or the return value of my_function() is None. How can I achieve this?

Answer 1

One way to approach this is as follows:

trigger = True
try:
    x = my_function()  # This can raise IndexError
    if x is None:
        raise ValueError
except (ValueError, IndexError) as e:
    if type(e) is IndexError:
        trigger = False
    do_something()

Otherwise, you may re-raise an error, but you will need nested try block, and I assume you don't want that.