Re^2: Concept map of data types

[programmer.perl]

in reply to Re: Concept map of data types
in thread Concept map of data types

Thanks,

Here, in your examples I found my mistake, instead of @ I wrote %, I corrected this. Last updated map is above, you can see.

Yesterday I look for a Data::Dumper in a CPAN but I didn't undesrtand how to use it. I am new in using cpan and modules. I red SYNOPSIS but didn't understand how to use them (code). Do you have any link that help me in this case? In cpan modules till now I could use just Date::Format.

[Athanasius]

Yesterday I look for a Data::Dumper in a CPAN but I didn't undesrtand how to use it.

Data::Dumper is a core module, so you can view its documentation in perldoc. See especially the EXAMPLES section.

HTH,

[aitap]

Data::Dumper can be used to do a lot of interesting things, but basically, you just need to use Data::Dumper and then print Dumper (anything).

It can be useful to pass a reference to the object you want to see, not just this object. For example, it's useful in case of AoH (array of hashes):

use Data::Dumper;
my @hashes = (
 { one => 1, two => 2, three => 3 },
 { one => 11, two => 22, three => 33 },
);                             
                               
print Dumper @hashes;          
print "-"x5,"\n";
print Dumper \@hashes;         
__END__
$VAR1 = {                      
          'three' => 3,        
          'one' => 1,          
          'two' => 2           
        };                     
$VAR2 = {                      
          'three' => 33,       
          'one' => 11,         
          'two' => 22          
        };                     
-----
$VAR1 = [                      
          {                    
            'three' => 3,      
            'one' => 1,        
            'two' => 2         
          },                   
          {                    
            'three' => 33,     
            'one' => 11,       
            'two' => 22        
          }                    
        ];     

...but it does not improve anything in case of reference to array of references to arrays:

my $reference = [              
 [ 7, 8, 9 ],
 [ 10, 11, 12 ],
];
print Dumper $reference;
print Dumper \$reference;
$VAR1 = [ 
          [ 
            7,
            8,
            9
          ],
          [ 
            10,
            11,
            12
          ]
        ];
$VAR1 = \[  
            [ 
              7,
              8,
              9
            ],
            [ 
              10,
              11,
              12
            ]
          ];

[2teez]

Hi,

You can use Data::Dumper like so:

use Data::Dumper;

my @abc =    #abc is an array of references to arrays
  ( [qw (q   w  e  r)], 
    [qw (1   x  3  r)], 
    [qw (qwe rt 434 )], 
  );

print Dumper ( \@abc );    ## pass array @abc as an array reference

my $abc =    #abc is an array reference that contains references to ar
+rays
  [ [qw (q   w  e  r)], 
    [qw (1   x  3  r)], 
    [qw (qwe rt 434 )], 
  ];

print Dumper ($abc);    ## pass the array reference

Both print the following:

$VAR1 = [
          [
            'q',
            'w',
            'e',
            'r'
          ],
          [
            '1',
            'x',
            '3',
            'r'
          ],
          [
            'qwe',
            'rt',
            '434'
          ]
        ];

Showing 'stringified perl data structures'. It shows you how your data is structured.
Hope this helps