Re: Why does the Perl conditional operator not do what I expect?

I am always tripping up over this, and like betterworld says, parentheses are the answer. I believe this also works, and may be slightly easier to get your head around/remember (it is for me anyway).

($condition) ? ($a=2) : ($a=3);
[download]

btw from previous experience, I found it quite difficult to super search or google for advice on this construct, as most search engines do not recognise most punctuation, and I for one did not know it was called 'ternary ?'.

update: p.s. in response to linuxer, say you wanted to do $condition ? $a=2 : $b=3, would ($condition) ? ($a=2) : ($b=3) then be the correct/advisible way to do it?

cheers
why_bird

........
Those are my principles. If you don't like them I have others.
-- Groucho Marx
.......

Comment on Re: Why does the Perl conditional operator not do what I expect? Select or Download Code

Replies are listed 'Best First'.
Re^2: Why does the Perl conditional operator not do what I expect? by AnomalousMonk (Archbishop) on Apr 20, 2009 at 13:01 UTC
say you wanted to do `$condition ? $a=2 : $b=3` would `($condition) ? ($a=2) : ($b=3)` then be the correct/advisible way to do it? It would be one way to do it with a ternary operator. Another way is shown below. Both are correct (i.e., compile without error). Which is 'advisable' depends on circumstances; I tend to prefer the ternary form below, but `if ($cond) { $a = 2 } else { $b = 3 }` seems the clearest and most advisable of all. `>perl -wMstrict -le "my $cond = shift; $a = $b = 99; ($cond ? $a : $b) = ($cond ? 2 : 3); print qq{a $a b $b}; " 0 a 99 b 3 >perl -wMstrict -le "my $cond = shift; $a = $b = 99; ($cond ? $a : $b) = ($cond ? 2 : 3); print qq{a $a b $b}; " 1 a 2 b 99` [download]	[reply] [d/l] [select]
Re^2: Why does the Perl conditional operator not do what I expect? by Bloodnok (Vicar) on Apr 20, 2009 at 11:04 UTC
Hmmm , ...I found it quite difficult to super search or google... - not if you search for it by name i.e. search terms: tertiary operator perl, - approx. 24,500 hits. A user level that continues to overstate my experience :-))	[reply]
Re^3: Why does the Perl conditional operator not do what I expect? by roboticus (Chancellor) on Apr 20, 2009 at 12:23 UTC
Bloodnok: and ternary operator yields approx 14.1k hits, operator "three arguments" yields about 38k hits, so even incorrect reasonable guesses will get you there, so long as you use words instead of punctuation. ...roboticus	[reply]
Re^3: Why does the Perl conditional operator not do what I expect? by why_bird (Pilgrim) on Apr 20, 2009 at 11:09 UTC
No, I appreciate that, but I didn't know what it was called :) Since discovering 'perlop' my life has become much easier! ........ Those are my principles. If you don't like them I have others. -- Groucho Marx .......	[reply]