Hi Team,
Tested code that prints a value for !$state when $state is initialized
with my $state = ();
#!/usr/local/bin/perl
#
#set $state to () to find out what !$state is
use strict;
use warnings;
my $state =();
print "\!\$state is:\t", !$state, "\n\n\n";
print "\$state is:", $state, "\n\n\n";
#end tested code
so to investigate this further, I want to look at what perl takes as
"Truth". I want to nail down for my own benefit the differences between
uninitialized, undef, initialized as a reference to an empty hash or
array or whatever. How these compare with the return value of undef()
etc.
Quick, to the Fine Manual!
perldoc perldoc tells me all about formatting and gives me the actually
useful switches for the purposes of finding documentation:
-f if I want documentation on a function
-q to 'grep' the perl faqs
Question:
How do I get an index or a table of contents? How do I find out how to search the
perldocs for
"control structures"
I've tried:
perldoc perldoc
perldoc -f if
perldoc -q control
perldoc -q index
perldoc -q contents
perldoc -q perldoc
eg
perldoc perltoot
gets me what looks like a nice OO tutorial, but how would I know it is
there unless I'd seen it in a post on a website someplace.
Thanks in advance.
Tim Johnson said:
>
>$state evaluates as true (I think that's what you're asking).
>
>####################################
>
>$state = {};
>
>if($state){
> print "\$state is true: $state\n";
>}else{
> print "\$state is false";
>}
>
>####################################
>
>$state is true because it's not empty.
>It's a reference to a hash that is empty.
>
>
>
>
>
>-----Original Message-----
>From: David Arnold [mailto:[EMAIL PROTECTED]
>Sent: Thursday, July 15, 2004 7:24 PM
>To: [EMAIL PROTECTED]
>Subject: !$state
>
>All,
>
>If:
>
>$state={};
>
>Then, what is:
>
>!$state
>
>
>--
>To unsubscribe, e-mail: [EMAIL PROTECTED]
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><http://learn.perl.org/> <http://learn.perl.org/first-response>
>
--
Kind regards,
Hal Ashburner
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