I'm just starting to play with references to create nested data structures. I've read through the Advanced Perl Programming (O'Reilly) on data structures and the Perl docs concerning the subject but I'm still a little shaky and/or missing something.

Basically I'm parsing a few log files to associate user name with given and last names. Not all entries have a last or given.

Sample log looks like this:

User: username1
   Last Name: last name1
   Given Name: given name1
User: username2
   Last Name: last name2
User: username3
   Given Name: given name3

I'm stepping through the log line by line and trying to create an array of hashes. Each hash has a username, givenname and lastname key. I can make the initial entry of a username but when I try to add a [last|given]name I can't seem to get the right syntax.

Specific problem line (#18 & #22):

$$user_list[$num_users -1]->{lastname} = $lastname;

Complete script: 

00    #!/usr/bin/perl
01
02    # parse the user list dump from nlist into 1 tsv file
03
04    open (NLIST, $ARGV[0]) or die "Can't open nlist results\n $!";
05    @nlist = <NLIST>;
06    close NLIST;
07
08    for $line (@nlist) {
09       # do not parse for the exceptions, all else do the following:
10       if ($line !~ /^[Object|Current|A total]/) {
11          # user | given | last name?
12          if ($line =~ /^User\: (\w+)\n/) {
13             $username = lc($1);
14             push @user_list, \{ "username" => $username, "lastname"
+ => "", "givenname" => ""};
15          } elsif ($line =~ /^\tLast Name: (\w+)\n/) {
16             $lastname = lc($1);
17             $num_users = scalar @user_list;
18             $$user_list[$num_users -1]->{lastname} = $lastname;
19          } elsif ($line =~ /^\tGiven Name: (.)+\n/) {
20             $givenname = $1;
21             $num_users = scalar @user_list;
22             $$user_list[$num_users -1]->{givenname} = $givenname; 
23         }
24       }
25    }
26    
27    for $user (@user_list) {
28       print "User: $$user->{username}\n";
29       print "\tLast: $$user->{lastname}\n";
30       print "\tGiven: $$user->{givenname}\n";
31    }

[download]

Any and all help is greatly appreciated. Thanks, Mark

Edit by tye

In reply to Dereferencing Array of Hashes by mxn_mark

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