Nilay Puri wrote:
>
> Can any one walk me thru this piece of code ::
>
> while(<STDIN>)
> {
> chomp ;
> $isbn =(split(/^_/, $_))[0] ; --- not able to understand what is
> being accessed (......)[0]
> unless ($KEYS{$isbn} ) ---- isbn is a scalar variable, how keys
> wok on it ?
> {
> print "$_\n" ;
> $KEYS{$isbn} =1 ;
> }
> }
Hi Nilay.
>From your question, I guess the code isn't your own? I've put some whitespace in
so that it's a bit more visible, like this:
while (<STDIN>) {
chomp;
$isbn = (split(/^_/, $_))[0]; # --- not able to understand what is being accessed
(......)[0]
unless ( $KEYS{$isbn} ) { # ---- isbn is a scalar variable, how keys wok on it ?
print "$_\n";
$KEYS{$isbn} = 1;
}
}
First of all, the line
$isbn = (split(/^_/, $_))[0];
is almost certainly not what was meant. It will put into $isdn either a
null string (if the first character of the record is an underscore) or
else a copy of the entire record. I can't guess what the interntion was.
As for the line that accesses the %KEYS hash, you're probably best off
reading
perldoc perldata
about how strings can be used to index hashes.
HTH,
Rob
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