Hello, Dear Monks,

I wish to construct an output file which merges the data from three input files. I did it with two input fils by using a hash table but I don't know how to do it with three files.

My two input files are excel csv files which have the following form 

cake_number;first_price 

cake_1;3;
cake_2;4;
cake_3;9;
cake_4;7;
cake_9;8;

[download]
and 
cake_number;second_price 

cake_1;5;
cake_2;5;
cake_3;5;
cake_6;9;
cake_10;1;

[download]

Here is the output file (I have not tested yet) 

cake_number;frist_price;second_price;

cake_1;3;5;
cake_2;4;5;
cake_3;9;5;

[download]

Here is my program with two input files 

my %hash_table_1;
open(INFILE_1, "<$infile_1");

while (my $line_1 = <INFILE_1>){
    my @Elements_1 = split ';', $line_1;
    chomp($Elements_1[1]);
    $hash_table_1{$Elements_1[0]} = $Elements_1[1];
}

my %hash_table_2;
open(INFILE_2, "<$infile_2");

while (my $line_2 = <INFILE_2>){
    my @Elements_2 = split ';', $line_2;
    chomp($Elements_2[1]);
    $hash_table_2{$Elements_2[0]} = $Elements_2[1];
}

my @KEYS_1 = keys(%hash_table_1);
my @KEYS_2 = keys(%hash_table_2);

my $key_1;

foreach $key_1(@KEYS_1){
    if ( defined $hash_table_2{$key_1}){
    print OUTFILE "$key_1;$hash_table_1{$key_1};$hash_table_2{$key_1}\
+n";      }
}
close OUTFILE;
close INFILE_1;
close INFILE_2;

[download]

I do not know how to do it if I add a third column "third price". Could you give me some advice ? Thanks a lot

In reply to hash table with three input files by steph_bow

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