On Thu, 2008-08-07 at 18:42 +0800, Jeff Pang wrote:
> Anees 写道:
> >
> > #!/usr/bin/perl
> > $maxRecords=20000;
> > $steps=100;
> >
> > $index=1;
> > $recCounter=0;
> > while (<> && defined){
>
>
> This is not right.
> defined is equal to defined($_), but here $_ go without value.
> For reading a file line by line, saying:
>
> while(<>) { ... }
>
> is enough.
>
> while(<>) {
> if (defined) {...}
> }
>
> this defined is useless. b/c if $_ is undefined in while(), the loop
> will be broken already.
>
> I guess you want to exclude the blank lines, then just say:
>
> next if /^$/;
>
>
>
> > if($recCounter > $maxRecords){ break; }
>
> break is a wrong statement.
> You should replace "break" with "last" here, perl does it not the same as C.
>
>
>
> > $index++;
> > }
>
> You could never use a explict variable for keeping the line number, perl
> has the built-in variable "$." for that purpose. see "perldoc perlvar".
>
> HTH.
>
I must point out that if you have the statement:
next if /^$/;
earlier in the loop, $index is counting the non-blank lines and is not
the same as "$."
--
Just my 0.00000002 million dollars worth,
Shawn
"Where there's duct tape, there's hope."
"Perl is the duct tape of the Internet."
Hassan Schroeder, Sun's first webmaster
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