> x = None
> result = (x is None and "" or str(x))
>
> print result, type(result)
>
> ---------------
> OUTPUT
> ---------------
> None <type 'str'>
>
>
> y = 5
> result = (y is 5 and "it's five" or "it's not five")
>
> print result
>
> -------------
> OUTPUT
> -------------
> it's five
>
> ...what's wrong with the first operation I did with x? I was expecting
> "result" to be an empty string, not the str value of None.
An empty string evaluates to False, so it then continues to the
other branch. Either of the following should suffice:
# return a non-empty string
x is None and "None" or str(x)
# invert the logic and return
# something in the "and" portion
x is not None and str(x) or ""
There are more baroque ways of writing the terniary operator in
python (although I understand 2.5 or maybe python 3k should have
a true way of doing this). My understanding is that one common
solution is something like
{True: "", False: str(x)}[x is None]
-tkc
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