[Python-Dev] Adding a conditional expression in Py3.0

Alexander J. Kozlovsky kozlovsky at mail.spbnit.ru
Thu Sep 29 22:23:02 CEST 2005

Guido van Rossum wrote:

> I did this for my favorite proposal, and ended up with the list shown
> further down below.
> I think they all looks great!

I'm sorry for my bad English

IMHO, if condition is nontrivial, then the syntax:

    expr1 if some complex condition else expr2

can be more hard to read as compared with:

    if some complex condition then expr1 else expr2

In the second form visual comparison of expr1 and expr2 is simpler
because its adjacent placement. For example, in expression

    'DO' if cmd == DO and flag == OK or x is None else 'DONT'

'DO' and 'DONT' visually divided and eyes must move there and back
for find the difference between them. As opposite, in expression

    if cmd == DO and flag == OK or x is None then 'DO' else 'DONT'

it is very easy to determine what is possible expression output.
It is a bit more readable from my point of view

Best regards,
 Alexander                            mailto:kozlovsky at mail.spbnit.ru

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