The cleanest(IMO) is this :
a = (predicate and [if_true_expr] or [if_false_expr])[0]
This would give you the necessary "short circuit" behaviour no matter
what.
a = predicate and if_true_expr or if_false_expr
works most of the time but should if_true_expr turns out to be 0 or
something like that(python False equvialent), the if_false_expr will
still be executed, that becomes a logic error. an example :
a = int_str is None and None or int(int_str)
a = [if_false_expr, if_true_expr][predicate]
This doesn't have the "short circuit" feature and the order is
reversed(harder to read for people familiar with ternary operator).
Cannot be used in some case. like this :
a = [0, int(int_str)][int_str is not None]
here int(int_str) may cause exception if None is a valid value.
The lambda form suggested by others is another variant of the first one
above where you get the short circuit feature but too complex to read.
I don't understand why people are so aganst ternary operator. It is a
must for list comprehension/generator expression(and I believe the
reason it has finally been approved), if/else block or try/except just
don't work in these situations.
Daniel Crespo wrote:
> Hi!
>
> I would like to know how can I do the PHP ternary operator/statement
> (... ? ... : ...) in Python...
>
> I want to something like:
>
> a = {'Huge': (quantity>90) ? True : False}
>
> Any suggestions?
>
> Thanks
>
> Daniel
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