reebee3 has asked for the wisdom of the Perl Monks concerning the following question:

Hello! This is the output I am trying to achieve... 

    $VAR1 = {

             'Tucson' => 'AZ',

             'Boston' => 'MA',

             'Jackson' => 'MS',

             'Dixon' => 'NM',

             'Denton' => 'TX',

             'Cincinnati' => 'OH'

           };

   1: Boston, MA

   2: Cincinnati, OH

   3: Denton, TX

   4: Dixon, NM

   5: Jackson, MS

   6: Tucson, AZ

[download]

I am having trouble getting the cities to sort alphabetically and am not sure how to incorporate the numbering on the alphabetical sort. The Dumper output is just fine.

This is what I have so far... 

 
#!/usr/bin/env perl 
use strict;
use warnings;
use autodie;
use Data::Dumper;

my %cities = (
    Tucson  => 'AZ',
    Boston  => 'MA',
    Jackson => 'MS',
    Dixon   => 'NM',
    Denton  => 'TX',
    Cincinnati   => 'OH',
);
    print Dumper(\%cities);
    

foreach my $place (sort { $cities{$a} cmp $cities{$b} } keys %cities) 
+{
    my $state = $cities{$place} ;
    print "$place, $state \n";
}

[download]

Thank you

Replies are listed 'Best First'.
Re: sorting hash alphabetically with numbering
by BrowserUk (Patriarch) on Oct 12, 2015 at 03:01 UTC

    Like this?:

    #! perl -slw
use strict;

my %cities = (
    Tucson  => 'AZ',
    Boston  => 'MA',
    Jackson => 'MS',
    Dixon   => 'NM',
    Denton  => 'TX',
    Cincinnati   => 'OH',
);

my @sorted = sort keys %cities;
my $n = 0;
printf "%d: %s, %s\n", ++$n, $_, $cities{ $_ } for @sorted;

__END__
C:\test>1144458
1: Boston, MA
2: Cincinnati, OH
3: Denton, TX
4: Dixon, NM
5: Jackson, MS
6: Tucson, AZ

    [download]
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[reply]
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      Yes, exactly. Thank you!

      It works perfectly, but I don't quite follow this line... 

      printf "%d: %s, %s\n", ++$n, $_, $cities{ $_ } for @sorted;

      [download]
[reply]
[d/l]

        printf takes a FORMAT: in this case, that's "%d: %s, %s\n". Those FORMATs are documented under the related function sprintf.

        The 'for @sorted' part is a statement modifier: documented under perlsyn: Statement Modifiers.

        Hopefully, the remaining parts are clear. If not, please specify what part(s) you're having difficulty with.

        — Ken

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Re: sorting hash alphabetically with numbering
by AnomalousMonk (Archbishop) on Oct 12, 2015 at 03:05 UTC

    TMI — Too Much Information. You're actually sorting by the values of the keys (i.e., the state codes) and not by the keys (the cities). 

    c:\@Work\Perl\monks>perl -wMstrict -MData::Dumper -le
"my %cities = (
      Tucson  => 'AZ',
      Boston  => 'MA',
      Jackson => 'MS',
      Dixon   => 'NM',
      Denton  => 'TX',
      Cincinnati   => 'OH',
  );
      print Dumper(\%cities);
  foreach my $place (sort keys %cities) {
      my $state = $cities{$place} ;
      print \"$place, $state \n\";
  }
"
$VAR1 = {
          'Cincinnati' => 'OH',
          'Tucson' => 'AZ',
          'Dixon' => 'NM',
          'Jackson' => 'MS',
          'Denton' => 'TX',
          'Boston' => 'MA'
        };

Boston, MA

Cincinnati, OH

Denton, TX

Dixon, NM

Jackson, MS

Tucson, AZ

    [download]

    Update 1: I was going to add some example code to handle the numbering, but BrowserUk beat me to it.

    Update 2: This might give you a better idea of what's going on in your original sort block: 

    c:\@Work\Perl\monks>perl -wMstrict -e
"my %cities = qw(
   Tucson AZ  Boston MA  Jackson MS  Dixon NM  Denton TX  Cincinnati O
+H
   );
 for my $place (sort { printf qq{'$cities{$a}' };   $cities{$a} cmp $c
+ities{$b}; } keys %cities) {
   print qq{\n '$place' in '$cities{$place}'};
   }
"
'OH' 'NM' 'TX' 'AZ' 'MS' 'OH' 'AZ' 'MA' 'MS' 'TX' 'TX'
 'Tucson' in 'AZ'
 'Boston' in 'MA'
 'Jackson' in 'MS'
 'Dixon' in 'NM'
 'Cincinnati' in 'OH'
 'Denton' in 'TX'

    [download]

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