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Compare common fields from two text files

Discussion in 'Perl' started by terrylau, Jan 26, 2010.

  1. terrylau

    terrylau New Member

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    Hi guys, Perl newbie here. Need help here. I've got two text file - File1.txt and File2.txt. The files consist of :

    File1.txt
    Field1 Field2 Field3 Field4 Field5
    A 1 1 1 A1
    B 2 2 2 B2
    C 3 3 3 C3
    D 4 4 4 D4
    E 5 5 5 E5
    F 6 6 6 F6

    File2.txt
    Field2 Field3 Field4
    1 1 1
    2 2 2
    3 3 3

    I want to check both files, and if both have the same values for Field2,Field3,Field4 - in this example, the output should be the lines from File1.txt
    A 1 1 1 A1
    B 2 2 2 B2
    C 3 3 3 C3

    It should do checking by line to whole file rather than line1 compare line1, line2 compare line2, etc.
    Meaning it should be something like this :

    Line1(File1.txt) compare all contents of File2.txt, print line from File1.txt with common values
    Line2(File1.txt) compare all contents of File2.txt, print line from File1.txt with common values
    Line3(File1.txt) compare all contents of File2.txt, print line from File1.txt with common values

    and not :

    Line1(File1.txt) compare Line1(File2.txt), print line from File1.txt if have common values
    Line2(File1.txt) compare Line2(File2.txt), print line from File1.txt if have common values
    Line3(File1.txt) compare Line3(File2.txt), print line from File1.txt if have common values


    Here's my code but I"m not too sure what's wrong as I'm seem to have the wrong output.
    Code:
     
      my %seen;
      my $line;
      my @data;
       
      open(A, "File1.txt") or die "...";
      while ($line = <A>)
                  {
                              @data = split(" ",$line);
                              ($Field2, $Field3, $Field4) = ($data[1], $data[2], $data[3]);
                              $seen{$Field2, $Field3, $Field4}= 1;
                  }
      close(A);
       
      open(B, "File2.txt") or die "...";
      while ($line = <B>)
                  {
                              @data = split(" ",$line);
                              ($Field2, $Field3, $Field4) = ($data[0], $data[1], $data[2]);
                              $seen{$Field2, $Field3, $Field4} +=2;
                  }
      close(B);
       
      while (my ($key, $val) = each %seen) {
        if ($val == 1) {
          # $key is in first file but not second
      print " File 1 - $Field2, $Field3, $Field4\n"
        } elsif ($val == 2) {
          # $key is in second file but not first
      print " File 2 - $Field2, $Field3, $Field4\n"
        } else {
          # key is in both files
      print " Both file - $Field2, $Field3, $Field4\n"
      }
      }
       
    
    Appreciate the help or suggestion for other ways to do this. Thanks.
     
  2. pradeep

    pradeep Team Leader

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    Here's it

    Code:
    #!/usr/bin/perl
    
    my %seen;
    my $line;
    my @data;
    
    open( A, "File1.txt" ) or die $!;
    my $line = <A>;    # first line
    while ( $line = <A> )
    {
        chomp($line);
        @data = split( " ", $line );
    	next unless(@data);
        ( $Field2, $Field3, $Field4 ) = ( $data[1], $data[2], $data[3] );
        $seen{"$Field2,$Field3,$Field4"} = 1;
    }
    close(A);
    
    open( B, "File2.txt" ) or die $!;
    my $line = <B>;    # first line
    while ( $line = <B> )
    {
        chomp($line);
        @data = split( " ", $line );
    	next unless(@data);
        ( $Field2, $Field3, $Field4 ) = ( $data[0], $data[1], $data[2] );
        $seen{"$Field2,$Field3,$Field4"} += 2;
    }
    close(B);
    
    while ( my ( $key, $val ) = each %seen )
    {
        if ( $val == 1 )
        {
            # $key is in first file but not second
            print " File 1 - $key\n";
        }
        elsif ( $val == 2 )
        {
            # $key is in second file but not first
            print " File 2 - $key\n";
        }
        else
        {
            # key is in both files
            print " Both file - $key\n";
        }
    }
    
     
    shabbir likes this.

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