in reply to Making a hash of making a hash of an array

I believe the logic in your for loop is incorrect, beside kabel's point about wrecking your hash by assigning to it after the loop, the while loop inside the for simply ends up assigning each line of the file to the hash 10 times 

foreach my $line (@record) {
($timestamp, $current_time, $funds, $action, $current_funds) = split "
+\t",$line;

# The values of $timestamp, $current_time, $funds, $action, $current_f
+unds never change in this while loop.
    while ($count < 10){
    
    $member{$timestamp} = [$current_time, $funds, $action, $current_fu
+nds];
    $count += 1;
    }
}

[download]

You want something like this: 

for my $line (@record[0..9]) {
  ($timestamp, $current_time, $funds, $action, $current_funds) = split
+ "\t",$line;
  $member{$timestamp} = [$current_time, $funds, $action, $current_fund
+s];
}

[download]

HTH

Replies are listed 'Best First'.
Re: Re: Making a hash of making a hash of an array
by jonnyfolk (Vicar) on Jun 04, 2003 at 05:33 UTC

    Thanks, pzbagel.

    After so many hours of trying to make it work you cannot imagine the relief I felt when I pasted your lines in and a table appeared as if by magic.

    I had thought that the 

    foreach my $line (@record)

    [download]
    would extract each line and place it in the hash. That is obviously not the case and I don't understand why. If you have a moment to explain i'd be grateful.

[reply]
[d/l]

      Actually, that's exactly what it was doing. The way your code was written, it would have inserted all the lines from the file into the hash(granted the nested while was reinserting that same hash values 10 times each). It was the line immediately after the foreach loop, as kabel already pointed out, which was resetting your your hash to just one key/value pair: 

      # This is the culprit!
%member = ( $timestamp => [$current_time, $funds, $action, $current_fu
+nds]);

      [download]

      That line was resetting the %member hash to the last values of $timestamp, et al. Removing that line would leave you with a hash with every line split and inserted. Now since you only wanted the last 10 lines, the for loop code I posted simply took an array slice from 0-9 and iterated over those, effectively letting the loop parse only the last 10 lines of the file.

      Hope that clears things up a bit.

[reply]
[d/l]

        Once again, I appreciate your help.

        I only put the "culprit" line in because what I had before was only giving the last line read out and I attempted to 'reformat' the hash as per the example on the html-template tutorial page. How wrong I was...!

        Your advice has made me realise that instead of the while ($count < 10){ #loop } I had used: 

        if ($count < 10){
    
    $member{$timestamp} = [$current_time, $funds, $action, $current_fu
+nds];
    $count += 1;
    }

        [download]
        all would have worked okay and I would have unwittingly missed out on a great deal of good advice...:)

        Thanks once again.

[reply]
[d/l]
[select]

In Section Seekers of Perl Wisdom