Execute code block if condition or exception

问题

With exceptions being so central to idiomatic Python, is there a clean way to execute a particular code block if an expression evaluates to True or the evaluation of the expression raises an exception? By clean, I mean an easy-to-read, Pythonic, and not repeating the code block?

For example, instead of:

try:
    if some_function(data) is None:
        report_error('Something happened')
except SomeException:
    report_error('Something happened') # repeated code

can this be cleanly rewritten so that report_error() isn't written twice?

(Similar question: How can I execute same code for a condition in try block without repeating code in except clause but this is for a specific case where the exception can be avoided by a simple test within the if statement.)

回答1:

Yes, this can be done relatively cleanly, although whether it can be considered good style is an open question.

def test(expression, exception_list, on_exception):
    try:
        return expression()
    except exception_list:
        return on_exception

if test(lambda: some_function(data), SomeException, None) is None:
    report_error('Something happened')

This comes from an idea in the rejected PEP 463.

lambda to the Rescue presents the same idea.

来源：https://stackoverflow.com/questions/46304716/execute-code-block-if-condition-or-exception