I don't know how well it would scale, but I'd build a hash from the first file ($objects{'object1'}=23.12;), then scan the second file. If the object in the second file has a defined hash, then print out the hashkey and both values..

Untested code... and I'm assuming a space delim. as per your examples..

open(FILE, "file1");
while(<FILE>){
  if(/(\S+)\s+(\S+)/){
    $hash{$1} = $2;
  }
}
close FILE;
open(FILE, "file2");
while(<FILE>){
  if(/(\S+)\s+(\S+)/){
    print "$1: $hash{$1} $2\n" if defined $hash{$1};
  }
}
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