Returning single or multiple values?

sschneid has asked for the wisdom of the Perl Monks concerning the following question:

I have the following code (a helper sub for Net::LDAP):

# Perform an LDAP query, returning results in a hash.
sub fetch {
    my $self = shift;
    %{$self->{'ARG'}} = @_;

    my ($r);

    my $result = $self->{'LDAP'}->search(
        base    => $self->{'ARG'}->{'source'},
        filter  => $self->{'ARG'}->{'filter'}
    );

    foreach my $entry ($result->all_entries()) {
        map {
            push my @a, $entry->get_value($_);
            if ($a[1]) {
                $r->{$entry->dn()}->{$_} = [ $entry->get_value($_) ];
            } else {
                $r->{$entry->dn()}->{$_} = $entry->get_value($_);
            }
        } $entry->attributes();
    }

    return $r;
}
[download]

...which works perfectly, and does exactly what I want. My only problem is that the assignment of values to a temporary array (@a) and then testing whether $a[1] exists as a way to tell whether $entry->get_value is returning multiple values or not seems... well, clumsy.

Is there a better way?

-s.

Comment on Returning single or multiple values? Select or Download Code

Replies are listed 'Best First'.
Re: Returning single or multiple values? by ccn (Vicar) on Aug 27, 2004 at 19:27 UTC
At first you do not check for existence of a second element of an array, but check it's truth. You can rewrite it like this: `foreach my $entry ($result->all_entries()) { foreach ( $entry->attributes() ) { my $ra = [ $entry->get_value($_) ]; $r->{$entry->dn()}->{$_} = @$ra > 1 ? $ra : $ra->[0]; } }` [download] Update: lexical $r renamed to $ra	[reply] [d/l]
Re^2: Returning single or multiple values? by sschneid (Deacon) on Aug 27, 2004 at 19:33 UTC
Thanks! -s.	[reply]
Re: Returning single or multiple values? by Arunbear (Prior) on Aug 27, 2004 at 19:25 UTC
Indeed there is: `foreach my $entry ($result->all_entries()) { foreach ($entry->attributes()) { my (undef, $val) = $entry->get_value($_) $r->{$entry->dn()}{$_} = $val ? [ $entry->get_value($_) ] : $entry->get_value($_); } }` [download] Update: but see ccn's reply below for a better solution.	[reply] [d/l]
Re: Returning single or multiple values? by bronto (Priest) on Aug 30, 2004 at 11:10 UTC
Why are you needless calling `get_value` twice? It doesn't come for free! Moreover, why are you calling `map` that way? Personally, I don't like using `map` throwing away its result; if I need a cycle I prefer using an explicit `foreach`, for example. Anyway, my 2c: `foreach my $entry ($result->all_entries()) { foreach my $attr ($entry->attributes()) { my @a = $entry->get_value($attr); $r->{$entry->dn()}->{$_} = @a > 1? \@a : $a[0] ; } }` [download] Ciao! `--bronto` The very nature of Perl to be like natural language--inconsistant and full of dwim and special cases--makes it impossible to know it all without simply memorizing the documentation (which is not complete or totally correct anyway). --John M. Dlugosz	[reply] [d/l] [select]


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