Class Dictionary
In: lib/more/facets/dictionary.rb
Parent: Object

Dictionary

The Dictionary class is a Hash that preserves order. So it has some array-like extensions also. By defualt a Dictionary object preserves insertion order, but any order can be specified including alphabetical key order.

Usage

Just require this file and use Dictionary instead of Hash.

  # You can do simply
  hsh = Dictionary.new
  hsh['z'] = 1
  hsh['a'] = 2
  hsh['c'] = 3
  p hsh.keys     #=> ['z','a','c']

  # or using Dictionary[] method
  hsh = Dictionary['z', 1, 'a', 2, 'c', 3]
  p hsh.keys     #=> ['z','a','c']

  # but this don't preserve order
  hsh = Dictionary['z'=>1, 'a'=>2, 'c'=>3]
  p hsh.keys     #=> ['a','c','z']

  # Dictionary has useful extensions: push, pop and unshift
  p hsh.push('to_end', 15)       #=> true, key added
  p hsh.push('to_end', 30)       #=> false, already - nothing happen
  p hsh.unshift('to_begin', 50)  #=> true, key added
  p hsh.unshift('to_begin', 60)  #=> false, already - nothing happen
  p hsh.keys                     #=> ["to_begin", "a", "c", "z", "to_end"]
  p hsh.pop                      #=> ["to_end", 15], if nothing remains, return nil
  p hsh.keys                     #=> ["to_begin", "a", "c", "z"]
  p hsh.shift                    #=> ["to_begin", 30], if nothing remains, return nil

Usage Notes

  • You can use order_by to set internal sort order.
  • #<< takes a two element [k,v] array and inserts.
  • Use ::auto which creates Dictionay sub-entries as needed.
  • And ::alpha which creates a new Dictionary sorted by key.

Methods

<<   ==   []   []   []=   alpha   auto   clear   delete   delete_if   dup   each   each_key   each_pair   each_value   empty?   fetch   first   has_key?   insert   inspect   invert   key?   keys   last   length   merge   merge!   new   new_by   order   order_by   order_by_key   order_by_value   pop   push   reject   reject!   reorder   replace   reverse   reverse!   select   shift   size   store   to_a   to_h   to_hash   to_s   unshift   update   values  

Included Modules

Enumerable

Public Class methods

Alternate to new which creates a dictionary sorted by key.

  d = Dictionary.alpha
  d["z"] = 1
  d["y"] = 2
  d["x"] = 3
  d  #=> {"x"=>3,"y"=>2,"z"=>2}

This is equivalent to:

  Dictionary.new.order_by { |key,value| key }

Alternate to new which auto-creates sub-dictionaries as needed.

  d = Dictionary.auto
  d["a"]["b"]["c"] = "abc"  #=> { "a"=>{"b"=>{"c"=>"abc"}}}

New Dictiionary.

Like new but the block sets the order.

Public Instance methods

def ==( hsh2 )

  return false if @order != hsh2.order
  super hsh2

end

Store operator.

  h[key] = value

Or with additional index.

 h[key,index] = value
each_pair()

Alias for each

merge!( hsh2 )

Alias for update

Keep dictionary sorted by a specific sort order.

Keep dictionary sorted by key.

  d = Dictionary.new.order_by_key
  d["z"] = 1
  d["y"] = 2
  d["x"] = 3
  d  #=> {"x"=>3,"y"=>2,"z"=>2}

This is equivalent to:

  Dictionary.new.order_by { |key,value| key }

The initializer Dictionary#alpha also provides this.

Keep dictionary sorted by value.

  d = Dictionary.new.order_by_value
  d["z"] = 1
  d["y"] = 2
  d["x"] = 3
  d  #=> {"x"=>3,"y"=>2,"z"=>2}

This is equivalent to:

  Dictionary.new.order_by { |key,value| value }
size()

Alias for length

[Validate]