How can I organize this data using Perl? - perl

Question

I am new to Perl. I have an input file such as:
a 7 5
b 8 2
a 3 2
b 4 1
c 6 1
How can I get output like
column_1_val, number_occurrence_column_1, sum_of_column_2, sum_of_column_3
For example
a 2 10 7
b 2 12 3
c 1 6 1

Answer 1

The program below is a possible solution. I have used the DATA file handle whereas you will presumably need to open an external file and use the handle from that.
use strict;
use warnings;
use feature 'say';
my %data;
while (<DATA>) {
my ($key, #vals) = split;
$data{$key}[0]++;
my $i;
$data{$key}[++$i] += $_ for #vals;
}
say join ' ', $_, #{$data{$_}} for sort keys %data;
__DATA__
a 7 5
b 8 2
a 3 2
b 4 1
c 6 1
output
a 2 10 7
b 2 12 3
c 1 6 1

Answer 2

That would be something like (untested):
while (<>) {
if (m/(\w+)\s+(\d+)\s+(\d+)/) {
($n, $r1, $r2) = ($1, $2, $3);
$nr{$n}++;
$r1{$n} += $r1;
$r2{$n} += $r2;
}
}
for $n (sort keys %nr) {
print "$n $nr{$n} $r1{$n} $r2{$n}\n";
}
This is a very quick-and-dirty way of doing what you described, but it should get you on your way.

Answer 3

Even i am not aware of perl.But in case you are concerned with the result.the below is the solution in awk.It might /might not help you.but in case u need it :
awk '{c[$1]++;a[$1]=a[$1]+$2;b[$1]+=$3}END{for(i in a)print i,c[i],a[i],b[i]}' file3

Answer 4

A slightly different take:
my %records;
while ( <> ) {
my #cols = split ' ';
my $rec = $records{ $cols[0] } ||= {};
$rec->{number_occurrence_column_1}++;
$rec->{sum_of_column_2} += $cols[1];
$rec->{sum_of_column_3} += $cols[2];
}
foreach my $rec ( map { { col1 => $_, %{ $records{ $_ } } }
sort keys %records
) {
print join( "\t"
, #$rec{ qw<col1 number_occurrence_column_1
sum_of_column_2 sum_of_column_3
>
}
), "\n"
;
}