I have a file with some navigation (x and y's) and needed to fill in
point between exiting points.
My in put file:
600000 6174210
600017 6174213
600028 6174206
600035 6174216
600045 6174209
For calculation I need to use line 1 and 2 for calculating one point
and then line 2 and 3 and so on ...
I solved it by using Xaviers tip on Tie::File:
use Tie::File;
tie my @line, 'Tie::File', $ARGV[0] or die "could not open $ARGV[0]: $!";
my $cnt1 = 0;
my $cnt2 = 0;
while ( $cnt1 < $ARGV[1] ) {
$cnt2++;
#print " $cnt1 $cnt2\n";
my @rec1 = split(' ', $line[$cnt1]);
my @rec2 = split(' ', $line[$cnt2]);
my $newin = (($rec1[0] - $rec2[0]) / 2) + $rec2[0];
my $newxl = (($rec1[1] - $rec2[1]) / 2) + $rec2[1];
print "@rec1\n";
print "$newin $newxl\n";
$cnt1 = $cnt2;
}
where $ARGV[1] is the number of lines in the file.
Could I have used an array as you mentioned in the bottom of your comment?
Thanks for the comment on "||" and "or" I was not aware of that.
On 7/15/05, John W. Krahn <[EMAIL PROTECTED]> wrote:
> Jakob Kofoed wrote:
> > Hi,
>
> Hello,
>
> > I would like to load a file to a hash so I will be able to call a
> > specific number in that hash:
> >
> > use strict;
> > use warnings;
> >
> > my %hash = ();
> > open IN, "< $ARGV[0]" || die "could not open $ARGV[0]\n";
>
> That will never die() because of the high precedence of the || operator.
> You need to either use open() with parentheses or use the lower
> precedence 'or' operator. You should also include the $! variable in
> the error message so you know why it died.
>
> open IN, "< $ARGV[0]" or die "could not open $ARGV[0]: $!";
>
>
> > my $cnt = "0";
>
> If you are going to use $cnt numerically why are you assigning a string
> to it? Why not just use the built-in $. variable?
>
>
> > while (<IN>) {
> > chomp;
> > %hash = ( $cnt => $_ );
>
> You are assigning a list to %hash which overwrites the hash each time
> through the loop. What you want to do is assign the value to a specific
> key.
>
> $hash{ $cnt } = $_;
>
> But if all of your keys are sequential numbers then you should just use
> an array instead:
>
> push @array, $_;
>
>
> > $cnt++;
> > }
> > print $hash{"837"};
> >
> > This works fine with the last line only! how do I append to my hash?
> > and secondly: here I use a counter to get a specific "line" in the
> > hash - does a hash have a "build in" counter to refer to?
>
>
> John
> --
> use Perl;
> program
> fulfillment
>
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