On Jan 11, 4:20 am, "s. keeling" <[EMAIL PROTECTED]> wrote:
> ISHWAR RATTAN <[EMAIL PROTECTED]>:
>
> > I am coming back toperlafter a long time.
>
> > The sample code these days also uses variable attribute my as:
>
> > my $inst = Extutils::Installed->new();
> > my @modules = $inst->modules();
>
> > Can any demistify 'my' for me??
>
> -----------------------------
> #!/usr/bin/perl
> # this just re-implements tail -1
> #
> # usage:
> # /this/file < /some/text/file.txt
> #
>
> my $last;
>
> while( <> ) {
> $last = $_;
> }
>
> print $last;
> -----------------------------
>
> Now, try with the "my $last;" *inside* the while(). That last print
> line won't have a clue what $last is.
>
That doesn't sound right to me. Scope doesn't change in a loop. All
of this code is in the same scope, so the print statement will work
fine.
If you move the loop to a subroutine, then the two $last variables
will be independant due to separate scopes:
my $last="foo";
$bar=scan_loop();
print $bar;
print $last;
sub scan_loop{
my $last;
while( <> ){
$last=$_;
return $last;
}
}
This will print out the last line and then "foo" because there are two
$last values, the one in the original scope and the one in the
subroutine scope.
-pedxing
