in reply to Re^3: Need help figuring out how to order/eval the numbers
in thread Need help figuring out how to order/eval the numbers

I am now stopped with my new test to implement new learnings...I read and reviewed other code and still lost...maybe I need a break or think of a better test prog to try out skills

need help here with doing a proper sub routine check on the values of a hash ref. while using the <=>

IF the value = value1 then print out to file

IF value of either is not the same then print those to a file

1 = 1
2 = 2
3 = 3
4 = 4
5 = 5

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1 = 2
2 = 2
3 = 4
4 = 7
5 = 5
6 = 6

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use strict;
use warnings;
use autodie;
use diagnostics;
use Data::Dump qw(dump);
my %seen;

open my $in,'<','./Test_Data.txt';

while(<$in>){
     my ($key,$value)= split /[\s=\s]+/; 
    $seen{$key}[0]=$value; 
    }
close $in;

#using ONE hashes to check key

open my $in1,'<','./Test_Data1.txt';

while(<$in1>){
    my ($key,$value)= split /[\s=\s]+/; 
    $seen{$key}[1]=$value if (exists $seen{$key});
}     
close $in1;
#dump \%seen;

#section uses as follows: ? conditional to write on different output f
+iles
#also, 1st sub to written by me... to check the values 

open my $out,'>','./OUT_test_data_keys_and_sorted_values_match.txt';
open my $out1,'>','./OUT_test_data_No_values_matched.txt';
foreach my $key ( sort { check_values()} keys %seen){
    if ($key){
        my $fh = defined $seen{$key}[0] && 
        defined $seen{$key}[1] ? $out:$out1;
        print $fh "$key => ",join(',',@{$seen{$key}}),"\n";
        }
    }
close $out;
close $out1;

#here is first SUBROUTINE checks that value [0] == value[1]
#my %number;

sub check_values{
    for my $key (sort {$a<=>$b} keys %seen){
        #don't know how ,where to get valueat [0],value at[1] from??wh
+o has the values? what is really (a and b) in, is it $_ or %seen? wha
+t am I really evaluating with,is it like this: $seen{$key}[0]=$a or $
+seen{$key}[1]=$b...completely lost...
        }

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Replies are listed 'Best First'.
Re^5: Need help figuring out how to order/eval the numbers
by roboticus (Chancellor) on Jun 25, 2015 at 02:23 UTC

    perlnewby:

    The function you give sort has one job: to tell sort which order you want between two items: $a and $b. If you want the value in $a to sort after the value in $b, your function needs to return 1. If you want it to sort before $b, return -1.

    So you don't need to figure out how to get the values, they're handed to you as $a and $b. You simply need to tell sort how to decide which order you want for any two values.

    $ cat foo.pl
use strict;
use warnings;

my @list = (qw(now is the time));

sub compare {
    my ($left, $right) = @_;
    print "Comparing $left and $right.\n";
    return  1 if $left gt $right;
    return -1 if $left lt $right;
    return  0;
}

print "BEFORE: ", join(" ", @list), "!\n";

@list = sort { compare($a,$b) } @list;

print "AFTER: ", join(" ", @list), "?\n";

$ perl foo.pl
BEFORE: now is the time!
Comparing now and is.
Comparing the and time.
Comparing is and the.
Comparing the and now.
AFTER: is now the time?

    [download]

    Update: Added punctuation for a bit of fun...

    ...roboticus

    When your only tool is a hammer, all problems look like your thumb.

[reply]
[d/l]

      Seriously, this should be posted with your little test code on the book I picked up! I need to find a better book...

      Now, I play with sub routines and play more with sort...I feel GOOD about Perl this morning...hopefully, some break through in my learning today ;-)

      I've briefly read, rather GLANCED, at a posting while trying to figure out the $a and the $b question I posted here. Any way, File::Compare(I think it was defined like this on google search)module be an option?

      Ringrazio tanto a tutti
[reply]
Re^5: Need help figuring out how to order/eval the numbers
by perlynewby (Scribe) on Jun 27, 2015 at 02:22 UTC

    I have written little test code that test out the order of the hash BUT ,out of curiosity, I want to call it from this little test program I've been bugging you about, can this be done? and how? I'd appreciate a pointer to read up on it and then I will try it out...I may have questions later but I want to read this first.

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