Transposing CSV data in Perl

Question

I am a Perl beginner and currently working on a Perl script to automate some of our tasks. One script that I\'m working on involves extracting performance data from our syst

Answer 1

Here is my Perl program to transpose row data into columns. A row starts with the headline name followed by one or more values. In my case I needed to remove the date (mm/dd/yyyy) from the headlines so the remainder of the headline field would be unique across multiple rows.

sub usage { << "EOF";

Convert rows to columns.
Remove dates from column headings. 

Usage:
    perl $0
Example:
   $0 data-to-transpose.txt

Source data:
    header1, row1Value1, row2Value2
    header2, row2Value1
    header3 11/31/2011, row3Value1, row3Value2
Output:
    header1, header2, header3
    row1Value1, row2Value1, row3Value1
    row1Value2, , row3Value2

EOF
}
#
#-------------------------------------------------------------------------------

use 5.010;
use strict;
use warnings;

# use Data::Dumper;
sub printColumns;

my $inFile = shift or die usage();
# @ARGV = ('.') unless @ARGV;

my @headers;        # Order list of column headers
my %data;           # map{colHeader, arrayColSourceData }
my $colCnt = 0;     # maximum number of columns in source data, header, value1, value2, ....
my $printColHeaders = 1;

my %hasharray; open (my $fh, "<", $inFile) or die "can't open the $inFile";
while (<$fh>) {
    chomp;
    my @parts = split /,/; 

    if (@parts > 1) {
        # Remove date from heading field
        (my $header = $parts[0]) =~ s/[0-9]+\/[0-9]+\/[0-9]+//;

        if (!exists $data{$header}) {
           push @headers, $header;
        }

        my $have = $data{$header};
        if (defined $data{$header}) {
            if ($printColHeaders == 1) {
                $printColHeaders = 0;
                foreach my $col (@headers) {
                    print "$col,";
                }
                print "\n";
            }

            printColumns();

            foreach my $col (@headers) {
                 $data{$col} = undef;
            }
        } 

        $data{$header} = \@parts;
        $colCnt = (@parts > $colCnt) ? @parts : $colCnt;
    }
} 

printColumns();
print "\n";

foreach my $col (@headers) {
    print "$col,";
}
print "\n";

#### Subs 
sub printColumns() {
    for my $row (1 .. $colCnt-1) {
        foreach my $colHeader (@headers) {
            my $colData = $data{$colHeader};
            if (defined $colData) {
                my $len=@$colData;
                if (defined $colData && $row < @$colData) {
                    print "$colData->[$row], ";
                } else {
                    print ", ";
                }
            } else {
                print ", ";
            }
        }
        print "\n";
    } 
}