#!/usr/bin/perl -w
use strict;
use Statistics::Basic::Mean;
use Statistics::Basic::StdDev;

print 'Start: ' . localtime() . $/;

my $filename = '224_APID003_report.csv';
open READ_IN, "<$filename"
	or die "I can't open $filename to read.\n";

## Extracting the label values first and storing them in an array
## saves re-sorting the hash every time 
## and removes the one-time-true condtional code from the loop
chomp( my $header = <READ_IN> );
my @hash_keys = split ',', $header;

my %HoA;

while (<READ_IN>) {
    chomp;
    pop_hash( $_ )
}
close READ_IN;

for( @hash_keys ) {
    next if m/(?:TIME|YEAR)/i;
    my @data = unpack 'd*', $HoA{ $_ }; ## Unpack each vector in turn
    my $count = @data;
    my( $hi, $low ) = ( sort{ $a <=> $b } @data ) [ -1, 0 ];
    my $mean = Statistics::Basic::Mean->new( \@data )->query;
    my $stddev = Statistics::Basic::StdDev->new( \@data )->query;
    printf "%-17s MIN:(%8g) MEAN( %8g) MAX:(%8g) STDDEV:(%8g) POINTS(%5d)\n",
    	$_, $low, $mean, $hi, $stddev, $count;
}

sub pop_hash {
	no warnings 'numeric'; ## Avoid warnings from non mumeric fields
    my @values = split( /,/, shift );

    ## Note: Sorting unnecessary as we stored the keys in an array in their original order!
    for( @hash_keys ) {
		## Accumulating data values as a string of packed doubles.
		## instead of an array of scalars
		## reduces memory consumption
        $HoA{ $_ } .=  pack 'd', 0 + shift @values;
    }
}

print 'Stop:  ' . localtime() . $/;
printf 'Check memory'; <STDIN>;

__END__
P:\test>463483
Start: Sat Jun  4 11:49:02 2005
224_P003PVNO      MIN:(       0) MEAN(        0) MAX:(       0) STDDEV:(       0) POINTS(99999)
224_P003PCKT      MIN:(       0) MEAN(        0) MAX:(       0) STDDEV:(       0) POINTS(99999)
224_P003SHDF      MIN:(       1) MEAN(        1) MAX:(       1) STDDEV:(       0) POINTS(99999)
224_P003ID        MIN:(       3) MEAN(        3) MAX:(       3) STDDEV:(       0) POINTS(99999)
224_P003SEGF      MIN:(       3) MEAN(        3) MAX:(       3) STDDEV:(       0) POINTS(99999)
224_P003SCNT      MIN:(   11466) MEAN(    11468) MAX:(   11470) STDDEV:( 1.41421) POINTS(99999)
224_P003PLEN      MIN:(      35) MEAN(       35) MAX:(      35) STDDEV:(       0) POINTS(99999)
224_MCDHANSGND    MIN:(       0) MEAN(        0) MAX:(       0) STDDEV:(       0) POINTS(99999)
224_MCDH5VSVOLT   MIN:( 4.96176) MEAN(  4.96176) MAX:( 4.96176) STDDEV:(6.51035e-013) POINTS(99999)
224_MCDH5VSCUR    MIN:(0.496248) MEAN( 0.496248) MAX:(0.496248) STDDEV:(8.18678e-013) POINTS(99999)
224_MCDH33VSVOLT  MIN:( 3.32078) MEAN(  3.32078) MAX:( 3.32078) STDDEV:(4.5306e-012) POINTS(99999)
224_MCDH33VSCUR   MIN:( 0.09408) MEAN(  0.09408) MAX:( 0.09408) STDDEV:(6.10623e-015) POINTS(99999)
224_MCDH25VSVOLT  MIN:( 2.51989) MEAN(  2.51989) MAX:( 2.51989) STDDEV:(3.87734e-012) POINTS(99999)
224_MCDH25VSCUR   MIN:(0.037647) MEAN( 0.037647) MAX:(0.037647) STDDEV:(7.57797e-014) POINTS(99999)
224_PBUSURBVOLT   MIN:(  6.9834) MEAN(  7.01162) MAX:( 7.01867) STDDEV:(0.0141077) POINTS(99999)
224_PEPURLCUR     MIN:(   1.275) MEAN(    1.293) MAX:(    1.32) STDDEV:(0.014697) POINTS(99999)
224_PBATV1        MIN:(0.247917) MEAN( 0.247917) MAX:(0.247917) STDDEV:(3.57547e-013) POINTS(99999)
224_PBATFIVOLT    MIN:(    5.83) MEAN(     5.83) MAX:(    5.83) STDDEV:(5.71099e-013) POINTS(99999)
224_PBATCUR       MIN:(   0.045) MEAN(    0.045) MAX:(   0.045) STDDEV:(5.21319e-014) POINTS(99999)
224_PBATCPOL      MIN:(      49) MEAN(       49) MAX:(      49) STDDEV:(       0) POINTS(99999)
224_PBATCPOLV     MIN:(   0.735) MEAN(    0.735) MAX:(   0.735) STDDEV:(5.01155e-013) POINTS(99999)
224_PEPSAVOLT     MIN:( 7.44399) MEAN(  7.44399) MAX:( 7.44399) STDDEV:(1.12834e-011) POINTS(99999)
224_PEPSACUR      MIN:(   1.575) MEAN(    1.575) MAX:(   1.575) STDDEV:(2.43805e-013) POINTS(99999)
224_PBATHV1       MIN:(0.125373) MEAN( 0.125373) MAX:(0.125373) STDDEV:(1.98896e-013) POINTS(99999)
224_PBATHV2       MIN:(0.125373) MEAN( 0.125373) MAX:(0.125373) STDDEV:(1.98896e-013) POINTS(99999)
224_PBATHV3       MIN:(0.125373) MEAN( 0.125373) MAX:(0.125373) STDDEV:(1.98896e-013) POINTS(99999)
224_PBATHV4       MIN:(0.125373) MEAN( 0.125373) MAX:(0.125373) STDDEV:(1.98896e-013) POINTS(99999)
224_PBATHV5       MIN:(0.125373) MEAN( 0.125373) MAX:(0.125373) STDDEV:(1.98896e-013) POINTS(99999)
224_PBATHV6       MIN:(0.125373) MEAN( 0.125373) MAX:(0.125373) STDDEV:(1.98896e-013) POINTS(99999)
224_PEP5VBM       MIN:( 5.27354) MEAN(  5.27354) MAX:( 5.27354) STDDEV:(7.62057e-012) POINTS(99999)
224_PBATV2        MIN:(       0) MEAN(        0) MAX:(       0) STDDEV:(       0) POINTS(99999)
224_AMAGCUR       MIN:( 0.13726) MEAN( 0.137599) MAX:(0.138108) STDDEV:(0.000415434) POINTS(99999)
224_MCDH21VRVOLT  MIN:( 2.09014) MEAN(  2.09014) MAX:( 2.09014) STDDEV:(4.21441e-013) POINTS(99999)
224_XRCVAGCGS     MIN:(0.019593) MEAN( 0.019593) MAX:(0.019593) STDDEV:(1.28682e-014) POINTS(99999)
224_XRCVCLSTR     MIN:(0.019593) MEAN( 0.019593) MAX:(0.019593) STDDEV:(1.28682e-014) POINTS(99999)
224_XRCVRFPS      MIN:(  20.753) MEAN(   20.753) MAX:(  20.753) STDDEV:(2.24532e-011) POINTS(99999)
Stop:  Sat Jun  4 11:50:03 2005
Check memory 52,808 kb