yeah...i do need to understand hashes better b/c I do not seem to get them, but I got it working:
for my $i ( keys %dub_hash ) {
my $key = "$i -- ";
if (keys (%{$dub_hash{$i}}) > 1) {
print $key, join( "\n" . ' ' x length
$key, keys %{ $dub_hash{ $i } } ),"\n";
}
}
thanks again. | [reply]
[d/l] |
##-- Create a HoHoH. 1st hash keyed by name, that accesses 2nd hash k
+eyed by UID, that accesses 3rd hash keyed by remaining items: gid,gec
+os and hostname --##
$dub_hash{$name}{$uid} = { # User data keyed by uid
gid => $gid,
gecos => $gecos,
host => $host,
So this code creating 3 hashes one with a key of name and the next with a key of uid and gid, gecos and host are values in the last hash?
thank you
| [reply]
[d/l] |
Yes. dub_hash is a hash. {$name} accesses an element in the hash, creating it if it didn't exist already.
{$name}{$uid} is shorthand for {$name}->{$uid} which implies the value accessed by $name is a hash reference. Again the hash element is generated if it didn't exist already.
= {...}; is an annonymous hash whose reference is assigned to the element accessed by {$name}{$uid}.
The result is a HoHoH - hash of hash of hash.
DWIM is Perl's answer to Gödel
| [reply]
[d/l]
[select] |
HoH
--------
'jblow' => {
'uid' => '2195',
'gecos' => 'Joe Blow,,,',
'gid' => '20'
},
snippet.....
( $name, $p, $uid, $gid, $gecos, $dir, $s ) = split( ':' );
$hash1{$name} -> {'uid'} = $uid;
$hash1{$name} -> {'gid'} = $gid;
$hash1{$name} -> {'gecos'} = $gecos;
HoHoH
----------
$VAR1 = {
'jblow' => {
'2195' => {
'gecos' => 'Joe Blow,,,',
'gid' => '20'
}
}
};
snippet......
$hash2{$name}{$uid} = {
gid => $gid,
gecos => $gecos,
};
I am now comparing so I grasp hashes and understand them more, in the first printed
dump of HoH, there are 2 hashes called "hash1 and "name". hash1 has a key of name with values of uid,gid and gecos? uid,gid and gecos are accessed only through name, joe blow in this case?
In the printed dump of HoHoH, there are 3 hashes called "hash2", "name" and "uid". hash2 has keys of name and uid with values of gid
and gecos? gid and gecos are only accessible through hash uid?
please provide any corrections.
thank you...again and the last ? | [reply]
[d/l] |