Gossamer Forum: General: Perl Programming: my c = (cond) ? a : b; question

Apr 24, 2002, 2:03 AM

yogi

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Apr 24, 2002, 2:03 AM

Post #1 of 5

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my c = (cond) ? a : b; question

What's wrong with the following expression (which doesn't work):

Code:
my $p = (defined $IN->param('p')) ? $IN->param('p') : $a->{p};

In my eyes this is completely equivalent to

Code:
 my $p; 
    if (defined $IN->param('p')) { 
	$p = $IN->param('p'); 
    } 
    else { 
	$a->{p}; 
    }

which works...

Ivan
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Iyengar Yoga Resources / GT Plugins

Apr 24, 2002, 2:20 AM

Paul

Veteran (19537 posts)

Apr 24, 2002, 2:20 AM

Post #2 of 5

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Re: [yogi] my c = (cond) ? a : b; question In reply to

Yeah it should work fine. What happens?

It should even work without the paretheses.

Apr 24, 2002, 4:01 AM

yogi

Veteran (2199 posts)

Apr 24, 2002, 4:01 AM

Post #3 of 5

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Re: [Paul] my c = (cond) ? a : b; question In reply to

$p always take the second value in the first version.... when I use the second version, it also takes the first value when it should.

Ivan
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Iyengar Yoga Resources / GT Plugins

Apr 24, 2002, 4:26 AM

Paul

Veteran (19537 posts)

Apr 24, 2002, 4:26 AM

Post #4 of 5

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Re: [yogi] my c = (cond) ? a : b; question In reply to

It works ok for me.

Code:
#!/perl/bin/perl 

use CGI qw/:standard/; 

my $foo = { p => 'foo' }; 
my $p   = defined param('p') ? param('p') : $foo->{p}; 

print header; 
print $p;

That prints foo when you don't enter a p parameter and prints bar if you do script.cgi?p=bar

Last edited by:

Paul: Apr 24, 2002, 4:29 AM

Apr 24, 2002, 5:01 AM

yogi

Veteran (2199 posts)

Apr 24, 2002, 5:01 AM

Post #5 of 5

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Re: [Paul] my c = (cond) ? a : b; question In reply to

Thanks Paul. Yes, it worked also for me.

The mistake I made was the following: p is the name of a checkbox field on a form. I thought that if the checkbox is unchecked param('p') will still be defined (and zero), but it isn't.

Ivan
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Iyengar Yoga Resources / GT Plugins