hey rob thanks from me too :-)
u shore did a great job of teaching
Regards
Saurabh
--- [EMAIL PROTECTED] wrote:
>
> Hey, Rob, thanks! That was really useful. Just
> from sitting in the
> background, reading these posts, I learn a lot.
>
> Thanks,
>
> Scott
>
> Scott E. Robinson
> SWAT Team
> UTC Onsite User Support
> RR-690 -- 281-654-5169
> EMB-2813N -- 713-656-3629
>
>
>
>
>
> "Rob Dixon"
>
>
> <[EMAIL PROTECTED] To:
> [EMAIL PROTECTED]
>
> .co.uk> cc:
>
>
>
> Subject: Re: References...
>
>
>
>
> 06/10/03 08:39 AM
>
>
>
>
>
>
>
>
>
>
>
> Hamish Whittal wrote:
> > Hi All,
> >
> > I'm still a little confused...
> > What is the difference between
> > %{$config_file->{$key}}
>
> Here, $config_file is a hash reference. If you print
> it it will
> display something like
>
> HASH(0x12345678)
>
> The hash it refers to is accessed by the value in
> $key, so if
> you had
>
> my $config_file = { K => { K2 => 'V2' } };
> my $key = 'K';
>
> then
>
> $config_file->{$key}
>
> would be equal to the anonymous hash { K2 => 'V2' }.
>
> This value is then dereferenced again as a hash, so
> if
> we have
>
> my %hash = %{$config_file->{$key}};
>
> then
>
> $config_file->{$key}
>
> %hash would be set to
>
> %hash = ( K2 => V2 );
>
>
>
> > %$config_file->{$key}
>
> Now this is something altogether different. You've
> discovered that you can use hash names as
> references,
> and this is an abuse of Perl and not to be
> encouraged!
>
> If you had
>
> my %config = ( K => { K1 => 'V1' } );
> my $config_file = \%config;
>
> then %$config_file is the same as %config, so you
> can access
> the element with
>
> $config{K}
> or
> $config_file->{K}
>
> What the book doesn't tell you, though, is that Perl
> will
> let you treat the hash name as a reference like this
>
> %config->{K}
>
> which is the same as
>
> %$config_file->{K}
>
> So you've dereferenced $config_file and then used it
> as a reference,
> so achieving nothing.
>
> To summarize:
>
> %$config_file->{$key}
>
> is the same as
>
> $config_file->{$key}
>
> and so is the same as the first case,
> %{$config_file->{$key}}
> without the additional level of dereferencing.
>
> But, as I said, don't use the second case!
>
> Cheers,
>
> Rob
>
>
>
>
>
> --
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=====
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
SAURABH SINGHVI
H-8,ROOM NO.291
IIT BOMBAY
POWAI
MUMBAI
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
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