Re: comparing two files for duplicate entries

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};
  }
}
[download]

Tom Melly, tom@tomandlu.co.uk

Comment on Re: comparing two files for duplicate entries Download Code

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Re^2: comparing two files for duplicate entries by Fletch (Bishop) on Sep 27, 2006 at 16:50 UTC
Yup, it's really just that simple (well, maybe `exists` rather than `defined`; but that's a minor nit). If your files are really, really big you probably want to use something like Berkeley_DB or one of the other DBM modules rather than reading everything into memory, but that's just an implementation detail; the basic algorithm remains the same.	[reply] [d/l] [select]
Re^2: comparing two files for duplicate entries by mk. (Friar) on Sep 27, 2006 at 16:54 UTC
or, just slightly different: `open(FILE1, "file1"); open(FILE2, "file2"); while(<FILE1>){ /(\S)\s+(\S)/; $hash{$1}=$2; } while(<FILE2>){ /(\S)\s+(\S)/; print "$1 $hash{$1} $2\n" if $hash{$1} }` [download] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ "one who asks a question is a fool for five minutes; one who does not ask a question remains a fool forever." mk at perl dot org dot br	[reply] [d/l]