Compare 2 csv files to get common values

perl -F"[|]" -lane 'if( @ARGV ){ $h{$F[1]}=$F[0] }elsif( $F[1]=$h{$F[0]} ){ print join"|",@F }' file2 file1 > output

Thanks for the quick reply. Would you be able to simplify the code slightly as your code is too efficient for a beginner to comprehend.

Many thanks!

Hi all,

I actually did write a code but somehow I am not able to get column 1 from file 1 to be displayed. Code is as per below:

#!/usr/bin/perl -s
#use strict;
use warnings;
my @so;

open(FILE1,"<$file1");
open(FILE2,"<$file2");
open(INFO, ">$file");  

while (<FILE2>) {
my @col = split /\|/;
$so{$col[1]}="$col[0]";
}

close FILE2;
open(FILE2,"<$file2");

my @arr1=<FILE1>;
my @arr2=<FILE2>;
close FILE1;
close FILE2;

my %chash;

for (@arr2){
chomp;
my($col1a,$col2a)=split(/\|/);
my $ckey="$col2a";

$chash{$ckey}=1;
}
for (@arr1){
chomp;
my($col1,$col2,$col3)=split(/\|/);
$col1="" if(!$col1);
my $ckey="$col1";

if($chash{$ckey}){
print INFO "$so{$col1}|$col1|$col3\n";

}
}
close INFO;


----------------------------------
When i run the code above an error is invoked saying that $so has not been initialized???

my @so;

did you mean
my %so;

perl -Mdiagnostics  Q_27321601.perl
Name "main::file" used only once: possible typo at Q_27321601.perl line 8 (#1)
    (W once) Typographical errors often show up as unique variable names.
    If you had a good reason for having a unique name, then just mention it
    again somehow to suppress the message.  The our declaration is
    provided for this purpose.
   
    NOTE: This warning detects symbols that have been used only once so $c, @c,
    %c, *c, &c, sub c{}, c(), and c (the filehandle or format) are considered
    the same; if a program uses $c only once but also uses any of the others it
    will not trigger this warning.
   
Name "main::file1" used only once: possible typo at Q_27321601.perl line 6 (#1)

Use of uninitialized value $file1 in concatenation (.) or string at
      Q_27321601.perl line 6 (#2)
    (W uninitialized) An undefined value was used as if it were already
    defined.  It was interpreted as a "" or a 0, but maybe it was a mistake.
    To suppress this warning assign a defined value to your variables.
   
    To help you figure out what was undefined, perl will try to tell you the
    name of the variable (if any) that was undefined. In some cases it cannot
    do this, so it also tells you what operation you used the undefined value
    in.  Note, however, that perl optimizes your program and the operation
    displayed in the warning may not necessarily appear literally in your
    program.  For example, "that $foo" is usually optimized into "that "
    . $foo, and the warning will refer to the concatenation (.) operator,
    even though there is no . in your program.

Yes.  my %so;

Thanks ozo u r the legend