> On Tuesday 06 July 2004 23:49, Bryan Harris wrote:
>>
>> I found this construct in the Perl Cookbook:
>>
>> $Current_Screen = param(".State") || "Default";
>>
>> I thought it was really cool because if the value of param(".State")
>> comes back undefined, the $Current_Screen variable gets set to
>> "Default".
>>
>> So the other day I wanted to do something similar:
>>
>> @somearray = @array1 || @array2;
>>
>> ... hoping that if @array1 was empty, @somearray would get the
>> contents of @array2. But it doesn't work -- @somearray gets (1).
>>
>> Is what I'm trying to do possible using a single command? Or is an
>> if-then-else the only way to do it?
>
> As you have noticed the logical or operator has problems with list
> context. You need to use the conditional operator instead.
>
> $ perl -le'
> @a = qw/a b c d/;
> @b = qw/e f g h/;
> @c = ();
> print "[EMAIL PROTECTED] = @a : [EMAIL PROTECTED] = @b : [EMAIL PROTECTED] = @c";
> @d = @a || @b;
> @e = @b || @c;
> @f = @c || @a;
> print "[EMAIL PROTECTED] = @d : [EMAIL PROTECTED] = @e : [EMAIL PROTECTED] = @f";
> @g = @a ? @a : @b;
> @h = @b ? @b : @c;
> @i = @c ? @c : @a;
> print "[EMAIL PROTECTED] = @g : [EMAIL PROTECTED] = @h : [EMAIL PROTECTED] = @i";
> '
> @a = a b c d : @b = e f g h : @c =
> @d = 4 : @e = 4 : @f = a b c d
> @g = a b c d : @h = e f g h : @i = a b c d
Looks like that was the only way to do it... Thanks for the confirmation
John, Gunnar.
- Bryan
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