in reply to Re^2: Splitting text into arrays
in thread Splitting text into arrays

You could use a HoA to store the data: col2 = key, col4 = values to be stored in the array. Then iterate thru the hash keys, send each value (an array) to a sub that returns the greatest value. The following does exactly that.

#!/usr/bin/perl

use Data::Dumper;
use strict;
my $k; 
my %hash; 
my @line;

# iterate thru data and store values in hash
while(<DATA>) {
    chomp($_);
    @line = split(",", $_);
    push @{ $hash{$line[2]} }, $line[4];
}
# hash structure (in case you are curious)
print "hash structure:\n";
print Dumper(\%hash);
print "\n";
# iterate thru hash
# send arrays to greatest sub
print "greatest values for each key:\n";
foreach $k (keys %hash) {
    print "$k: " . &greatest( $hash{$k} ) . "\n";
}

#return greatest value
sub greatest() {
    my $arr = shift;
    my @a = sort { $b <=> $a } @{ $arr };
    return $a[0];
}

exit;

__DATA__
2004,21,21,1,16.00
2004,21,21,1,16.25
2004,22,22,1,18.00
2004,22,22,1,18.25

[download]
output:
hash structure:
$VAR1 = {
          '22' => [
                    '18.00',
                    '18.25'
                  ],
          '21' => [
                    '16.00',
                    '16.25'
                  ]
        };

greatest values for each key:
22: 18.25
21: 16.25

[download]
hope this helps,
davidj

Replies are listed 'Best First'.
Re^4: Splitting text into arrays
by perl_seeker (Scribe) on Jun 23, 2004 at 12:57 UTC
    Hi David,
    thanks a lot for your help, much appreciated.I did manage to get my code to work using an array of arrays itself(with the help of Happy's and Mr.Muskrat's code ), but maybe you have done it in a better way.I've included my code at the bottom of the post.Actually, I found out later that I need to keep track of the 'month'of the year as well, which is stored in column 3.So suppose the data looks like 
    2004,21,21,1,16.00
2004,21,21,1,16.25
2004,22,22,1,18.00
2004,22,22,1,18.25
2004,21,21,2,16.00
2004,21,21,2,16.25
2004,22,22,2,18.00
2004,22,22,2,18.25

    [download]
    So we need to keep track of the col 2='21' rows for col3='1'and col3='2'and again col 2='22'rows for col3='1' and col3='2', and so on. How would you change your code to do that? Also I need to have the 'day' and 'month' in double digit format('01' instead of 1 for example).

    My actual data has much longer rows.Here's what one looks like: 
    2004,21,1,1,16.00,1600,18.62,20.28,16.86,3.225,1001,33.95,33.53,40.2,0
+,0,97.2,1.782,105.3,56.92,0,82.2

    [download]
    And here' my code,assuming values of only '21' and '22' for 'day', and '1' and '2' for 'month' for all to see and comment on :) (thanks for your patience!) 
    #!/usr/bin/perl
use strict;
use warnings;
my @data;

open(DAT, '<', 'testing.txt') or die $!;

while (<DAT>) {
chomp;
push @data, [split(/,/)];                   
                     #store in array of arrays
}

close (DAT);

my $count=0;

for my $row (0..$#data){ 
                         
                    #iterate over each row by index 

              $count++;
              #print "\nThe number of rows:";
              #print "\n $count";
                      
    for my $column(0..$#{$data [$row]}){

                   #iterate over each column by index 

   #print "row $row, column $column:$data[$row][$column]\n";

           #display using the notation from the arrow rule
                                          
           #the data in the row 1, column 1

              #print $data [1][1],"\n";      
              #print $data [1]->[1],"\n";    #Rule 2
              #print $ {$data [1]}[1],"\n";  #Rule 1
    }
}   

#print "\nThe number of rows:";
#print "\n $count";

open OUT, '>dailyrecords.xml' or die $!;
print OUT "\n<AnnualWeatherRecord>";

my @max_drybulb;

for (my $m=1;$m<=2;$m++){

for (my $d=21;$d<=22;$d++){

 #print "\n$i";
 #print"\n$n";
   
 my @drybulb=map { $_->[11] } grep { (($_->[2] == $d) && ($_->[3] == $
+m)) } @data;
 my @wetbulb=map { $_->[12] } grep { (($_->[2] == $d) && ($_->[3] == $
+m)) } @data;
 my @rainfall=map { $_->[4] } grep { (($_->[2] == $d) && ($_->[3] == $
+m)) } @data;

 my $hyphen="-";
 my @dates = map { "$_->[2]$hyphen$_->[3]$hyphen$_->[0]" }  grep { (($
+_->[2] == $d) && ($_->[3] == $m)) } @data;

 my $date=&senddate(@dates);
 
 #print "The date for each of the sets:";
 #print"\n@dates\n";  
 
 #print"\nThis set of data:";
 #print"\n@drybulb\n"; 

 #print"\nThis set of data:";
 #print"\n@wetbulb\n"; 

 #print"\nThis set of data:";
 #print"\n@rainfall\n"; 
 
 my $max_drybulb=&maxtemp(@drybulb);
 #print"\n$max_drybulb"; 
 
 my $min_drybulb=&mintemp(@drybulb);
 #print"\n$min_drybulb"; 
 
 my $max_wetbulb=&maxtemp(@wetbulb);
 #print"\n$max_wetbulb"; 
 
 my $min_wetbulb=&mintemp(@wetbulb);
 #print"\n$min_wetbulb";
 
 my $prec=&totrain(@rainfall);
 #print"\n$prec"; 
 
 print OUT "\n<DailyWeatherRecord>";
 
 print OUT"\n\t<date>$date</date>";
 
 print OUT "\n\t<temperature>";
 
 print OUT "\n\t\t<maxdrybulb units";
 print OUT "=\"degrees-centigrade\" number=\"$max_drybulb\"/>";
 
 print OUT "\n\t\t<mindrybulb units";
 print OUT "=\"degrees-centigrade\" number=\"$min_drybulb\"/>";
 
 print OUT "\n\t\t<maxwetbulb units";
 print OUT "=\"degrees-centigrade\" number=\"$max_wetbulb\"/>";
 
 print OUT "\n\t\t<minwetbulb units";
 print OUT "=\"degrees-centigrade\" number=\"$min_wetbulb\"/>";
 
 
 print OUT "\n\t</temperature>";
  
 print OUT "\n\t<totalrainfall units";
 print OUT "=\"mm/hr\" number=\"$prec\"/>";
  
 print OUT "\n</DailyWeatherRecord>";
   
 print OUT "\n\n\n\n";
 
 }
}

print OUT "\n</AnnualWeatherRecord>";
close (OUT);

sub maxtemp

{

my @max=@_; 

 foreach my $item(@max){

  #print "\nThe item:";
  #print"\n$item";
  
  }
  
  my $max=$_[0];
  for (@max) { $max = $_ if $_ > $max } 
  return $max; 
  
}
1;

sub mintemp
    
{     
    
my @min=@_; 

my $min=$_[0];
  for (@min) { $min = $_ if $_ < $min } 
  return $min; 
 
}
1;

sub totrain

{
my @prec=@_; 

#print "\n@prec\n";

my $tot=0;

  foreach my $ritem(@prec){

     $tot=$tot + $ritem; 
      
    }

    return $tot;
}

1;


sub senddate{

my @dat=@_; 
 
 foreach my $ditem(@dat){
    
     return $ditem;      

    }

  }

1;

    [download]
    thanks,
    perl seeker:)
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