#!/usr/bin/perl

use warnings;
use strict;
use Data::Dumper;
use Scalar::Util qw(looks_like_number);

my $data = [];
while (<DATA>) {
	chomp;
	if (/^(\w{1,2})$/) {
		push(@$data, [$1]);
	} elsif (looks_like_number($_)) {
		push(@{$$data[-1]}, $_);
	}
}
print Dumper($data);

__DATA__
C
 -2.3242E-003
 1.32423
 0.34243E+002
 -3.23134
MD
 0.34243E+002
 -3.23134