It does sound like homework, but joachim's been around for a bit and I've never heard him come up with a homework question before. Still, I think you've found the balance between helpful hinting and harmful hinting.

Update: I looked at joachim's home node and saw that he first logged in yesterday. My memory was faulty--I stand corrected.

Nope.... not homework. However I am flattered. This is a project for myself. It was something triggered my a conversation with one of my friends .... who said it couldn't be done. I see how quickly you monks have cobbled up text messages rather than just pluck down script. I must surmise that it's not that easy. Perhaps we should begin..... I have all night. #!/usr/bin/perl -w use strict; my $infile = shift; my $outfile = shift; open (IN, $infile) || die "can't open $infile: $!"; open (OUT, ">$outfile")|| die "can't open $outfile: $!"; while (<IN>) { chomp; my @fields = split /,/; #let's see what you can place here to make it work...... #Sorry about the mess.... but it looks better when I typed #out the thing in the first place. #BTW..... If this can't be done... to bad .... I'll just have #to go back to the book and maybe in year or two.... I'll be #able to write the script myself..... I'd rather not wait #that long..... thanks # Joachim close (IN); close (OUT); __END__

If you put your code inside <code> and </code> - tags, it would be far easier for us to read the code.
You might want to check out Writeup Formatting Tips.

neophyte Niederrhein.pm

#!perl -w

use strict;

my @lines;

while (<>) {
  push @lines, $_;
  shift @lines if @lines > 10;
}

chomp(@lines);

my @cols;
my $total = 0;

for (@lines) {
  @cols = split /:/;
  $total += $cols[3];
}
my $average = $total / (@lines || 1);
  # if no lines, avoid division by zero

print "Average of column 3 for the last ", scalar(@lines),
      " days: $average\n";
[download]

Update: Have to specify $_ in the call to push. Bad chipmunk! No acorns!

Just a little more Help here..... and I think it will work. I added some stuff to make the script load a file and output a log file. However there is some error in the script that I cannot resolve. Could someone please have a look....?? while we are editing the $text line..... could you also include the value of the most resent value entered in col3

#!/usr/bin/perl -w
       $infile = shift;
       $outfile = shift;
       
       open(IN, $infile) || die("Can't open input file $infile - $!");
       open(OUT, ">$outfile") || die("Can't open output file $outfile 
+- $!");

       use strict;
       my $text;
       my @lines;

       while (<>) {
         push @lines;
         shift @lines if @lines > 10;
       }

       chomp(@lines);

       my @cols;
       my $total = 0;

       for (@lines) {
         @cols = split /:/;
         $total += $cols[3];
       }
       my $average = $total / (@lines || 1);
         # if no lines, avoid division by zero

       
 ***** error here*****      $text= "Average of column 3 for the last "
+ ;#, scalar(@lines)," days: $average\n";
       


      print OUT "$text\n";
    
       close IN;
       close OUT ;
[download]

So the message in the Data.log file would read "<Filename> Average is <average> the last was <most resent entry for col3>" Thank you.. this has been good experience..... wish something like this was in the book I bought. joachim

Quote:

  $text= "Average of column 3 for the last " ;
             #, scalar (@lines)," days: $average\n";
[download]

Originally, that was a print statement, in which the commas were fine. With a scalar assignment, the commas should be replaced with concatenation:

$text = "Average of column 3 for the last " .
              scalar(@lines) . " days: $average\n";
[download]

or with join:

$text = join '', "Average of column 3 for the last ",
                       scalar(@lines), " days: $average\n";
[download]

or with a single interpolated string, or with sprintf... There's more than one way to do it.
 

The last line is at @lines[-1]; one way to get the most recent value is: my $last = (split /:/, $lines[-1])[3]; The ( )[3] is called a list slice. It's basically a short way of doing:

my @tmp = split /:/, $lines[-1];
my $last = $tmp[3];
[download]

Instead of assigning to the array @tmp and then looking up index 3, the list slice just does the index directly on the list. They give the same results, though, so use whichever is clearer.

You might want to read from your IN file.
Try <IN> instead of just <>.


Editorial: Instead of just cut and pasting chipmunk's code, try to understand what it does. Pick up Learning Perl, browse the other book reviews & purchase other worthy recommended books