1-line idiom to replace if blocks

[Robin Munn]

Y2KYZFR1 <jarrodhroberson at yahoo.com> wrote:
> "Jonathan P." <jbperez808 at yahoo.com> wrote in message news:<3e2cf624 at post.usenet.com>...
>> **** Post for FREE via your newsreader at post.usenet.com ****
>> 
>> I hate code that takes up too many lines and
>> have come up with the ff. idiom to replace
>> many 4 line if statements:
>> 
>> result=[value-if-false,value-if-true][condition]
>> 
>> This idea could also be applied as a compact
>> switch block replacement in certain cases.
>> 
> 
> God I feel sorry for anyone that has to come behind you and work on
> any code you ever write. If you are this lazy not to write out a
> simple if statement where other people can come behind you and
> understand it.
> 
> The entire idea behind Python even more so than other languages is
> maintance and readablity and you whack jobs just insist on making it
> convoluted and obfuscated!
> 
> It does not show how clever you are, just how lazy and inconsiderate
> you are. I have fired people for less than this personally!

Let's keep the heat down, shall we? Here, have an iced tea. :-)

Actually, there are occasional times when being able to express an
if-then-else statement in a single expression is very useful
(*cough*lambda*cough*). Most of the time, writing out the complete
if-then-else is better, yes. But there may be times when using a 1-line
idion may result in cleaner-looking code. Let's say you're registering a
bunch of callback functions:

    # The idiom [false_val,true_val][condition] is equivalent to the C
    # idiom (condition ? true_val : false_val)...
    register_callback(1, lambda retval: ['Error','OK'][bool(retval)])
    register_callback(2, lambda retval: ['Error','OK'][bool(retval)])
    register_callback(3, lambda retval: ['Error','OK'][bool(retval)])
    register_callback(4, lambda retval: ['Error','OK'][bool(retval)])
    register_callback(5, lambda retval: ['Error','OK'][bool(retval)])
    register_callback(6, lambda retval: ['Error','OK'][bool(retval)])

And so on. This example is somewhat contrived, but not extremely so,
unfortunately. I expect I will encounter occasional times when I'll need
to use a a?b:c-like idiom and nothing else will do...

-- 
Robin Munn <rmunn at pobox.com>
http://www.rmunn.com/
PGP key ID: 0x6AFB6838    50FF 2478 CFFB 081A 8338  54F7 845D ACFD 6AFB 6838