NAME

Data::Object::Hash

ABSTRACT

Data-Object Hash Class

SYNOPSIS

  use Data::Object::Hash;

  my $hash = Data::Object::Hash->new({1..4});

DESCRIPTION

Data::Object::Hash provides routines for operating on Perl 5 hash references. Hash methods work on hash references. Users of these methods should be aware of the methods that modify the array reference itself as opposed to returning a new array reference. Unless stated, it may be safe to assume that the following methods copy, modify and return new hash references based on their function.

METHODS

This package implements the following methods.

new

  # given 1..4

  my $hash = Data::Object::Hash->new(1..4);
  my $hash = Data::Object::Hash->new({1..4});

The new method expects a list or hash reference and returns a new class instance.

self

  # given $hash

  my $self = $hash->self();

The self method returns the calling object (noop).

roles

  # given $hash

  $hash->roles;

The roles method returns the list of roles attached to object. This method returns a Data::Object::Array object.

rules

  my $rules = $hash->rules();

The rules method returns consumed rules.

clear

  # given {1..8}

  $hash->clear; # {}

The clear method is an alias to the empty method. This method returns a Data::Object::Hash object. This method is an alias to the empty method.

count

  # given {1..4}

  my $count = $hash->count; # 2

The count method returns the total number of keys defined. This method returns a Data::Object::Number object.

defined

  # given {1..8,9,undef}

  $hash->defined(1); # 1; true
  $hash->defined(0); # 0; false
  $hash->defined(9); # 0; false

The defined method returns true if the value matching the key specified in the argument if defined, otherwise returns false. This method returns a Data::Object::Number object.

delete

  # given {1..8}

  $hash->delete(1); # 2

The delete method returns the value matching the key specified in the argument and returns the value. This method returns a data type object to be determined after execution.

each

  # given {1..8}

  $hash->each(sub{
      my $key   = shift; # 1
      my $value = shift; # 2
  });

The each method iterates over each element in the hash, executing the code reference supplied in the argument, passing the routine the key and value at the current position in the loop. This method supports codification, i.e, takes an argument which can be a codifiable string, a code reference, or a code data type object. This method returns a Data::Object::Hash object.

each_key

  # given {1..8}

  $hash->each_key(sub{
      my $key = shift; # 1
  });

The each_key method iterates over each element in the hash, executing the code reference supplied in the argument, passing the routine the key at the current position in the loop. This method supports codification, i.e, takes an argument which can be a codifiable string, a code reference, or a code data type object. This method returns a Data::Object::Hash object.

each_n_values

  # given {1..8}

  $hash->each_n_values(4, sub {
      my $value_1 = shift; # 2
      my $value_2 = shift; # 4
      my $value_3 = shift; # 6
      my $value_4 = shift; # 8
      ...
  });

The each_n_values method iterates over each element in the hash, executing the code reference supplied in the argument, passing the routine the next n values until all values have been seen. This method supports codification, i.e, takes an argument which can be a codifiable string, a code reference, or a code data type object. This method returns a Data::Object::Hash object.

each_value

  # given {1..8}

  $hash->each_value(sub {
      my $value = shift; # 2
  });

The each_value method iterates over each element in the hash, executing the code reference supplied in the argument, passing the routine the value at the current position in the loop. This method supports codification, i.e, takes an argument which can be a codifiable string, a code reference, or a code data type object. This method returns a Data::Object::Hash object.

empty

  # given {1..8}

  $hash->empty; # {}

The empty method drops all elements from the hash. This method returns a Data::Object::Hash object. Note: This method modifies the hash.

eq

  # given $hash

  $hash->eq; # exception thrown

This method is a consumer requirement but has no function and is not implemented. This method will throw an exception if called.

exists

  # given {1..8,9,undef}

  $hash->exists(1); # 1; true
  $hash->exists(0); # 0; false

The exists method returns true if the value matching the key specified in the argument exists, otherwise returns false. This method returns a Data::Object::Number object.

filter_exclude

  # given {1..8}

  $hash->filter_exclude(1,3); # {5=>6,7=>8}

The filter_exclude method returns a hash reference consisting of all key/value pairs in the hash except for the pairs whose keys are specified in the arguments. This method returns a Data::Object::Hash object.

filter_include

  # given {1..8}

  $hash->filter_include(1,3); # {1=>2,3=>4}

The filter_include method returns a hash reference consisting of only key/value pairs whose keys are specified in the arguments. This method returns a Data::Object::Hash object.

fold

  # given {3,[4,5,6],7,{8,8,9,9}}

  $hash->fold; # {'3:0'=>4,'3:1'=>5,'3:2'=>6,'7.8'=>8,'7.9'=>9}

The fold method returns a single-level hash reference consisting of key/value pairs whose keys are paths (using dot-notation where the segments correspond to nested hash keys and array indices) mapped to the nested values. This method returns a Data::Object::Hash object.

ge

  # given $hash

  $hash->ge; # exception thrown

This method is a consumer requirement but has no function and is not implemented. This method will throw an exception if called.

get

  # given {1..8}

  $hash->get(5); # 6

The get method returns the value of the element in the hash whose key corresponds to the key specified in the argument. This method returns a data type object to be determined after execution.

grep

  # given {1..4}

  $hash->grep(sub {
      shift >= 3
  });

  # {3=>5}

The grep method iterates over each key/value pair in the hash, executing the code reference supplied in the argument, passing the routine the key and value at the current position in the loop and returning a new hash reference containing the elements for which the argument evaluated true. This method supports codification, i.e, takes an argument which can be a codifiable string, a code reference, or a code data type object. This method returns a Data::Object::Hash object.

gt

  # given $hash

  $hash->gt; # exception thrown

This method is a consumer requirement but has no function and is not implemented. This method will throw an exception if called.

head

  # given $hash

  $hash->head; # exception thrown

This method is a consumer requirement but has no function and is not implemented. This method will throw an exception if called.

invert

  # given {1..8,9,undef,10,''}

  $hash->invert; # {''=>10,2=>1,4=>3,6=>5,8=>7}

The invert method returns the hash after inverting the keys and values respectively. Note, keys with undefined values will be dropped, also, this method modifies the hash. This method returns a Data::Object::Hash object. Note: This method modifies the hash.

iterator

  # given {1..8}

  my $iterator = $hash->iterator;
  while (my $value = $iterator->next) {
      say $value; # 2
  }

The iterator method returns a code reference which can be used to iterate over the hash. Each time the iterator is executed it will return the values of the next element in the hash until all elements have been seen, at which point the iterator will return an undefined value. This method returns a Data::Object::Code object.

join

  # given $hash

  $hash->join; # exception thrown

This method is a consumer requirement but has no function and is not implemented. This method will throw an exception if called.

keys

  # given {1..8}

  $hash->keys; # [1,3,5,7]

The keys method returns an array reference consisting of all the keys in the hash. This method returns a Data::Object::Array object.

le

  # given $hash

  $hash->le; # exception thrown

This method is a consumer requirement but has no function and is not implemented. This method will throw an exception if called.

length

  # given {1..8}

  my $length = $hash->length; # 4

The length method returns the number of keys in the hash. This method return a Data::Object::Number object.

list

  # given $hash

  my $list = $hash->list;

The list method returns a shallow copy of the underlying hash reference as an array reference. This method return a Data::Object::Array object.

lookup

  # given {1..3,{4,{5,6,7,{8,9,10,11}}}}

  $hash->lookup('3.4.7'); # {8=>9,10=>11}
  $hash->lookup('3.4'); # {5=>6,7=>{8=>9,10=>11}}
  $hash->lookup(1); # 2

The lookup method returns the value of the element in the hash whose key corresponds to the key specified in the argument. The key can be a string which references (using dot-notation) nested keys within the hash. This method will return undefined if the value is undef or the location expressed in the argument can not be resolved. Please note, keys containing dots (periods) are not handled. This method returns a data type object to be determined after execution.

lt

  # given $hash

  $hash->lt; # exception thrown

This method is a consumer requirement but has no function and is not implemented. This method will throw an exception if called.

map

  # given {1..4}

  $hash->map(sub {
      shift + 1
  });

The map method iterates over each key/value in the hash, executing the code reference supplied in the argument, passing the routine the value at the current position in the loop and returning a new hash reference containing the elements for which the argument returns a value or non-empty list. This method returns a Data::Object::Hash object.

merge

  # given {1..8}

  $hash->merge({7,7,9,9}); # {1=>2,3=>4,5=>6,7=>7,9=>9}

The merge method returns a hash reference where the elements in the hash and the elements in the argument(s) are merged. This operation performs a deep merge and clones the datasets to ensure no side-effects. The merge behavior merges hash references only, all other data types are assigned with precendence given to the value being merged. This method returns a Data::Object::Hash object.

ne

  # given $hash

  $hash->ne; # exception thrown

This method is a consumer requirement but has no function and is not implemented. This method will throw an exception if called.

pairs

  # given {1..8}

  $hash->pairs; # [[1,2],[3,4],[5,6],[7,8]]

The pairs method is an alias to the pairs_array method. This method returns a Data::Object::Array object. This method is an alias to the pairs_array method.

reset

  # given {1..8}

  $hash->reset; # {1=>undef,3=>undef,5=>undef,7=>undef}

The reset method returns nullifies the value of each element in the hash. This method returns a Data::Object::Hash object. Note: This method modifies the hash.

reverse

  # given {1..8,9,undef}

  $hash->reverse; # {8=>7,6=>5,4=>3,2=>1}

The reverse method returns a hash reference consisting of the hash's keys and values inverted. Note, keys with undefined values will be dropped. This method returns a Data::Object::Hash object.

set

  # given {1..8}

  $hash->set(1,10); # 10
  $hash->set(1,12); # 12
  $hash->set(1,0); # 0

The set method returns the value of the element in the hash corresponding to the key specified by the argument after updating it to the value of the second argument. This method returns a data type object to be determined after execution.

slice

  # given {1..8}

  my $slice = $hash->slice(1,5); # {1=>2,5=>6}

The slice method returns a hash reference containing the elements in the hash at the key(s) specified in the arguments. This method returns a Data::Object::Hash object.

sort

  # given $hash

  $hash->sort; # exception thrown

This method is a consumer requirement but has no function and is not implemented. This method will throw an exception if called.

tail

  # given $hash

  $hash->tail; # exception thrown

This method is a consumer requirement but has no function and is not implemented. This method will throw an exception if called.

unfold

  # given {'3:0'=>4,'3:1'=>5,'3:2'=>6,'7.8'=>8,'7.9'=>9}

  $hash->unfold; # {3=>[4,5,6],7,{8,8,9,9}}

The unfold method processes previously folded hash references and returns an unfolded hash reference where the keys, which are paths (using dot-notation where the segments correspond to nested hash keys and array indices), are used to created nested hash and/or array references. This method returns a Data::Object::Hash object.

values

  # given {1..8}

  $hash->values; # [2,4,6,8]
  $hash->values(1,3); # [2,4]

The values method returns an array reference consisting of the values of the elements in the hash. This method returns a Data::Object::Array object.

ROLES

This package inherits all behavior from the folowing role(s):

• Data::Object::Role::Detract

• Data::Object::Role::Dumper

• Data::Object::Role::Output

• Data::Object::Role::Throwable

• Data::Object::Role::Type

RULES

This package adheres to the requirements in the folowing rule(s):

• Data::Object::Rule::Collection

• Data::Object::Rule::Comparison

• Data::Object::Rule::Defined

• Data::Object::Rule::List

cpanm Data::Object

perl -MCPAN -e shell
install Data::Object