[Python-ideas] "else" expression ":"

[Chris Angelico]

On Fri, Apr 19, 2013 at 12:21 AM, Philipp A. <flying-sheep at web.de> wrote:
> no, this is different; it’s not for booleans, but for assertions, and could
> be used for e.g. exhaustive switches, e.g. it would make the first test in
> the following unnecessary:
>
> if spam not in {"a", "b", "c"}:
>     throw new ValueError("spam {} should be a, b, or c!".format(spam))
> if spam == "a":
>     foo()
> elif spam == "b":
>     bar()
> else:
>     baz()

Or alternatively, you could write it as:

if spam == "genuine watch":
    foo()
elif spam == "buy a college degree":
    bar()
elif spam == "rich guy wants to move money offshore":
    baz()
else:
    raise ValueError("Unrecognized spam '%s'!" % spam)

That removes the need to pre-check and match your if block.

ChrisA