Hi,
I'm having trouble with the following. I'm relatively new to Perl so any help would be appreciated

I have two files e.g. 

file 1
------
a 0
c 1
d 1
e 3
f 0

file 2
------
a 0
b 0
c 0
d 0
e 0
f 0

[download]
I need to compare column 1 of file2 with column1 of file1
If file2 has an extra record that isn't in file1 then a new file needs to be created which is a copy of file1 but has this new record in (in sorted order)
e.g. 
file3
-----
a 0
b 0
c 1
d 1
e 3
f 0

[download]
The code I have for this so far (which doesn't work) is 
   open FIRST,"file1" or die "Can't open file1: $!\n";
   open LAST,"file2" or die "Can't open file2: $!\n";
   open NEW,">file3" or die "Can't open file3: $!\n";
   chomp (my @last=<LAST>);
   
   my %names;
   @names {<FIRST>} = ();

   foreach my $name (@last) {
      next if exists $names { $name }or
      print NEW "$name\n";
   }

   close FIRST;
   close LAST;
   close NEW;

[download]
This is just creating file3 as a complete copy of file2.

How do I get it to just compare the first element of each record ?
How do I get the new record inserted in the correct order in the new file ?
Any help appreciated, I'm really struggling with the logic on this one

In reply to file compare and populate by Anonymous Monk

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