For review: PEP 308 - If-then-else expression

William wilk-spamout at flibuste.net
Fri Feb 7 22:44:46 CET 2003


What about 
a = exp if cond
could it be like
a = exp if cond else None


anyway, +1, i'm agree with Dan Schmidt <dfan at dfan.org> writes:

> I am so keen on having a ternary operator in Python that I would
> probably vote yes on any proposal that was made.
> 
> I dislike
> 
>   if test:
>       x = a
>   else:
>       x = b
> 
> not because it is longer than
> 
>   x = a if test else b
> 
> but because I think the intent of the code is much more clear if one
> says "x is the result of this computation depending on test" than if
> one says "if test is true, evaluate this body of code, otherwise
> evaluate this other body, and by the way they both happen to assign a
> value to x."  My appreciation for the former comes partly from using
> languages like Lisp, where there is no distinction between statements
> and expressions, and partly from using functional languages, where
> you really do have to decide what x is going to be all in one fell
> swoop.  I find that putting the logic for computing x in one place
> leads to fewer errors (for one thing, you don't have to type 'x'
> twice).
> 
> OK, so I would probably vote 'yes' on almost any proposal, but seriously,
> this one seems fine to me.  The order of operands seemed weird at first,
> but I kind of like the fact that when you're reading the code, "a if
> test else b" reads like a noun, because the first thing you encounter
> is 'a' rather than the test.  That is much more 'Englishy' to me than
> encountering the condition first.
> 
> I don't worry so much about the way this can be abused by putting in
> the middle of other expressions as in Guido's examples.  There are
> plenty of language constructs that you can abuse if you try hard
> enough, even in Python.
> 
> Dan
> 
> -- 
> http://www.dfan.org

-- 
William Dode - http://flibuste.net




More information about the Python-list mailing list