open FILE, '<', ...
my @numbers;
while( <DATA> } {
    push @numbers, m[^[ ]*[0-9]+[ ]*$] ? 0+$_
         : m[^[ ]*[0-9A-Z]+[ ]*$]i ? hex()
         : die "Bad number at $.";
}
## That hex() would do all of that for you and more is irrelevant