Question

Making a total hash of hashes

Asked by: trevor1940

Hi

I'm making a right hash of this.

Creating a news web page so each user ($Jnum)  can choose not to veiw news they have seen

later in the script i get all the news items and loop through based on there newsID
The idea  beeing if it has been seen it s not shown

There will only be one JNUM but 0 1 or meny News IDs

what am i doing wrong


use CGI;
use DBI;
 
my $cgi = new CGI;
my $JNum = $cgi->peram("JNum");
 
## to test 
$JNum = 'J123';
 
## Connect to DB
 
my $cmd = "select disinct news_id,jnum from seen where jnum= '$JNum';
$sth= $dbh->prepare("$cmd");
$sth->execute();
 
## Create a hash
my %seen;
 
while (my @val = $syh-> fetchrow_arrray())
  {
     my $newsID= $val[0];
     my $jnum=$val[1];
     print "NewsID = $newsID \t $jnum = $jnum\n";   ## OK Here
     $seen($newsID}={jnum=>$jnum};
  }
 
## to get out
for my $jnum (sort {$b<=> $a} keys %seen)
  {
    "$JNum has seen $seen{$newsID}{$jnum}}\n";  ## NOT OK
  }

                                  
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Asked On
2009-10-08 at 02:02:03ID24795156
Topic

Perl Programming Language

Participating Experts
1
Points
500
Comments
5

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Answers

 

by: ozoPosted on 2009-10-08 at 05:08:54ID: 25524407


#did you mean
print "$JNum has seen $seen{$newsID}{jnum}\n";  ## NOT OK

 

by: ozoPosted on 2009-10-08 at 05:16:14ID: 25524485

  $seen{$newsID}={jnum=>$jnum};
  }
 
## to get out
for my $jnum (sort {$b<=> $a} keys %seen)
  {
    print "$JNum has seen $seen{$jnum}{jnum}}\n";  ## NOT OK
  }

#But if you just did
   $seen{$newsID}=$jnum;
  }
 
#then you could do
for my $jnum (sort {$b<=> $a} keys %seen)
  {
    print "$JNum has seen $seen{$jnum}\n";  ## NOT OK
  }
#although it may make more sense to write that as
for my $newsID (sort {$b<=> $a} keys %seen)
  {
    print "$JNum has seen $seen{$newsID}\n";  ## NOT OK
  }

 

by: trevor1940Posted on 2009-10-08 at 06:50:15ID: 25525322

may be I have't explaned my self but i'm not getting what i expected
newsID is a interger
JNUM is the users number

whitin the while loop the print staitment out puts
going in
NewsID = 40 \t jnum =J123
NewsID = 46 \t jnum =J123
NewsID = 47 \t jnum =J123

Coming out all i'm getting is

J123 has seen J123  
J123 has seen J123  
J123 has seen J123  


what i need is

J123 has seen 40
J123 has seen 46
J123 has seen 47  

Thanx

 

by: ozoPosted on 2009-10-08 at 07:06:47ID: 25525533

for my $jnum (sort {$b<=> $a} keys %seen)
  {
    "$JNum has seen $seen{$newsID}{
Your loop variable is $jnum, but your string uses $JNum and $newsID
you probably want
for my $jnum (sort {$b<=> $a} keys %seen)
  {
    print "$jnum has seen $seen{$jnum}{jnum}\n"
assuming that you haven't changed
$seen($newsID}={jnum=>$jnum};  
except to change ( to {
$seen{$newsID}={jnum=>$jnum};
#this is equivalent to $seen{$newsID}{jnum} = $jnum; assuming that you never assigned  anything else to $seen{$newsID}

 

by: trevor1940Posted on 2009-10-14 at 03:48:30ID: 31638625

Hi
I eventualy solved the issue having done what you sugested I whent back to basics and found one of the Jnum's had a white space in it so wasn't matching.

Thanks for your help

20120131-EE-VQP-002

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