Right, but you don't have to presize it. Just push entries onto it as you parse them.
For instance, to invent a stupid-simple data format, and demonstrate parsing it and doing a thing or two with the data once parsed:
#!/usr/bin/env perl5
use strict;
use warnings;
my @clients;
my %tmp;
while(<DATA>)
{
chomp;
# Assume a format of "Type Data"
my ($type, $data) = split / /;
# If it's a MAC address, save off our pre-existing record (if any)
+,
# and start a new one.
if($type eq "MAC")
{
if(keys %tmp)
{
# Have to unroll a copy here, otherwise the next line empt
+ies
# it out.
push @clients, { (%tmp) };
%tmp = ();
}
$tmp{MAC} = $data;
}
# RSSI and SNR just get saved
$tmp{RSSI} = $data if $type eq "RSSI";
$tmp{SNR} = $data if $type eq "SNR";
}
# Save the 'last' one if we fell off the end
push @clients, \%tmp if keys %tmp;
# Show it
use Data::Dumper; print Dumper \@clients;
# Find a given entry
sub showmacsnr
{
my $mac = shift;
my @ba = grep { $_->{MAC} eq $mac } @clients;
if(@ba)
{
my $ent = $ba[0];
print "MAC $mac has SNR $ent->{SNR}\n";
}
else
{
print "Can't find MAC $mac\n";
}
}
showmacsnr("ba:98:76:54:32:10");
showmacsnr("thi:is:is:nt:re:al");
# Sample data
__DATA__
MAC 01:23:45:67:89:ab
RSSI 12
SNR 18
MAC ba:98:76:54:32:10
RSSI 7
SNR 3
So you end up with output like:
% ./tst.pl
$VAR1 = [
{
'RSSI' => '12',
'SNR' => '18',
'MAC' => '01:23:45:67:89:ab'
},
{
'SNR' => '3',
'RSSI' => '7',
'MAC' => 'ba:98:76:54:32:10'
}
];
MAC ba:98:76:54:32:10 has SNR 3
Can't find MAC thi:is:is:nt:re:al