in reply to Re: comparing 2 files problem
in thread comparing 2 files problem

# A version that also checks for lines in file2 that are not in file1:

open(FILE1, '<file1.txt') or die("Cannot open first file: $!.\n");
open(FILE2, '<file2.txt') or die("Cannot open second file: $!.\n");

%file1 = map { $_ => 1 } <FILE1>;
%file2 = map { $_ => 1 } <FILE2>;

foreach (keys(%file1)) {
   if ($file2{$_}) {
      print("Found in both files: $_");
   } else {
      print("Found only in first file: $_");
   }
}

foreach (keys(%file2)) {
   unless ($file1{$_}) {
      print("Found only in second file: $_");
   }
}

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Re^3: comparing 2 files problem
by ikegami (Patriarch) on Sep 07, 2004 at 18:54 UTC 
    # This version adds difference counts:

open(FILE1, '<file1.txt') or die("Cannot open first file: $!.\n");
open(FILE2, '<file2.txt') or die("Cannot open second file: $!.\n");

$file1{$_}++ while (<FILE1>);
$file2{$_}++ while (<FILE2>);

foreach (keys(%file1)) {
   if ($file2{$_}) {
      $diff = $file2{$_} - $file1{$_};
      if ($diff) {
         if ($diff < 0) {
            print("Found in first file $diff times more than in second
+ file: $_");
         } else {
            print("Found in second file $diff times more than in first
+ file: $_");
         }
      } else {
         print("Found in both files an equal number of times: $_");
      }
   } else {
      print("Found only in first file ($file1{$_} times): $_");
   }
}

foreach (keys(%file2)) {
   unless ($file1{$_}) {
      print("Found only in second file ($file2{$_} times): $_");
   }
}

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