use strict;
use warnings;

#opening the file for reading
open FH,"<data_input" or die "Can't open file : $!\n";
my @line;
while ( <FH> )
{
        if ( /(obj[1-9]*)/ )
        {
                my $line = $';
                my $val=0;
                @line = split(' ',$line);
                $val += $_ for @line;
                print "Sum : $val\n";
        }
}

Sum : 0.42196
Sum : 1.03072
Sum : 1.2758