(Complex)Data Manipulation

[rupesh]

Greetings! I seek the help of fellow monks once again. This is with regard to a friend of mine, who gave me a csv containing a database dump.
Below is a sample of the dump.

Date   Product   Quantity   Imported_From
1/2/04 Shirts     32         Australia
1/9/04 Shoes      234        Asia
2/12/04 Caps      109        UK
4/4/04 Shoes      6          Asia
4/4/04 Shirts     12         Australia
5/6/04 Shirts     398        Australia
.....
......

There are only 3 regions.
One or more products can be imported from one or many regions on a sin
+gle date.
No single column is unique.
There are many products, at the last count, it was 34.

What is needed is a summary of the report on a monthly basis. This would help in analyzing import-sales ratio for every month. (There is a similar dump for sales. That is a simpler one which does not include the 'region' field.) Output monthly report should look like:

Jan
Product Asia   Australia   UK   Total_Imported
Shirts  178    12          744  934
Shoes  ...
...
(products whose total is zero can be omitted)

Feb
Product Asia   Australia   UK   Total_Imported
....

I've worked on this for more than a couple of hours now using hashes and makeing '$date_$product' as key and quantity as its value. Using more hashes to seperate the regions. I've also tried to write to temp files and re-creating them for each month.

Is there a simple way to get the whole thing done in a single loop?
I'd appreciate any comments/thoughts from you folks.

Many thanks!

[NetWallah]

I think what you are looking for is a AOHOH, but my preference would be to let the database (SQL) do the aggregation and grouping.

The AOHOH would be:

 my @db;
 $db[$monthNumber]->{ProductName}{RegionName} = $Quantity;

 # Loop through Month..
 for (0..11){ #Cycle through Months, assuming zero-based
    next unless my %prod = %{$db[$_]}; # Any data there ?
   print "Some MONTH $_ header here\n";  
  foreach (sort keys %prod){
       my %region = %{$prod{$_}};
        # $region{RegionName} now has the qty to be printed
        # Hopefully, you get the idea now...
    }

 }

Needless to say, the code above is untested..

[rupesh]

AOHOH was what I was looking for.
Even though I'm done with the job, I'm benchmarking all the other algorithms that fellow monks have provided.
Many Thanks (Again)!

[poqui]

Oracle SQL-wise its pretty easy:

select product, sum(decode(region, 'asia', quantity,0)) as "Asia", sum( decode(region, 'australia',quantity,0)) as "Australia", sum( decode(region, 'UK',quantity,0)) as "UK", sum(quantity) as "Total Imported"
from whateverthetablenameis
group by product

AKA: Pivot report.

[saintmike]

I've worked on this for more than a couple of hours now using hashes and makeing

Any reason you didn't post the code you created so we could point out which parts need improvement?

Anyway, you're gathering data in three dimensions: By month, within the month by product, within the product by country. This cries for a multi-dimensional hash.

Here's an example grabbing the input with a regular expression, setting up a hash and printing out an incomplete result, but you should be able to fill in the gaps:

my $data   = join '', <DATA>;

my $by_month = {};

while($data =~ /^(\d+).*?(\w+) +(\d+) +(\w+)/mg) {
   print "Capturing $1 $2 $3 $4\n";
   $by_month->{$1}->{$2}->{$4} += $3;
}

for my $month (1..12) {
    print "Month: $month\n";
    for my $product (qw(Shirts Shoes Caps)) {
        printf "%7s ", $product;
        for my $country (qw(Asia Australia UK)) {
            printf "%6d ", 
              $by_month->{$month}->{$product}->{$country} || 0;
        }
        print "\n";
    }
}

__DATA__
1/2/04 Shirts     32         Australia
1/9/04 Shoes      234        Asia
2/12/04 Caps      109        UK
4/4/04 Shoes      6          Asia
4/4/04 Shirts     12         Australia
5/6/04 Shirts     398        Australia

which prints out the following:

Month: 1
 Shirts      0     32      0 
  Shoes    234      0      0 
   Caps      0      0      0 
Month: 2
 Shirts      0      0      0 
  Shoes      0      0      0 
   Caps      0      0    109 
Month: 3
 Shirts      0      0      0 
  Shoes      0      0      0 
   Caps      0      0      0 
Month: 4
 Shirts      0     12      0 
  Shoes      6      0      0 
   Caps      0      0      0

[TedPride]

Very neat, though it assumes a rather precise format. My solution is more adaptive, if a good deal more messy:

@mon = ('','Jan','Feb','Mar','Apr','May','Jun','Jul','Aug','Sep','Oct'
+,'Nov','Dec');

$_ = <DATA>; chomp;
$n{$_} = $c++ for split /\t/;

for (<DATA>) {
    chomp; split /\t/;

    @date = split /\//, $_[$n{'Date'}];
    $product = $_[$n{'Product'}];
    $country = $_[$n{'Imported_From'}];
    $quantity = $_[$n{'Quantity'}];

    $countries{$country} = () if !exists $countries{$country};
    $totals{$date[2]}{$date[0]}{$product}{$country} += $quantity;
}

@countries = sort keys %countries;

for (sort {$a <=> $b} keys %totals) {
    $year = $totals{$_};
    for (sort {$a <=> $b} keys %$year) {
        $month = $year->{$_};
        print "$mon[$_]\n";
        print join("\t", 'Product', @countries, 'Total'), "\n";
        for (sort keys %$month) {
            print;
            $product = $month->{$_};
            $total = 0;
            for (@countries) {
                print "\t".$product->{$_};
                $total += $product->{$_};
            }
            print "\t$total\n";
        }
        print "\n";
    }
}

__DATA__
Date    Product    Quantity    Imported_From
1/2/04    Shirts    32    Australia
1/9/04    Shoes    234    Asia
2/12/04    Caps    109    UK
4/4/04    Shoes    6    Asia
4/4/04    Shirts    12    Australia
5/6/04    Shirts    398    Australia

You can have any number of fields in any order, and the records can also be out of order. You're not limited to three countries either. Results are given in tab delimited format, perhaps not the most pretty thing to use, but I didn't feel like messing with prints after spending so much time writing the algorithm.

[holli]

...containing a database dump.

Why, if I may ask, don´t you use the means of the database to do grouping and reporting? That would be much more natural to me.