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Dictionary

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

Acknowledgments

Dictionary is a ported of OrderHash 2.0 Copyright (c) 2005 Jan Molic.

People who have contributed to this class since then include:

Copyright (c) 2005, 2009 Jan Molic, Thomas Sawyer

Public Class Methods

[](*args) click to toggle source
# File lib/hashery/dictionary.rb, line 65
def [](*args)
  hsh = new
  if Hash === args[0]
    hsh.replace(args[0])
  elsif (args.size % 2) != 0
    raise ArgumentError, "odd number of elements for Hash"
  else
    while !args.empty?
      hsh[args.shift] = args.shift
    end
  end
  hsh
end
alpha(*args, &block) click to toggle source

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 }
# File lib/hashery/dictionary.rb, line 97
def alpha(*args, &block)
  new(*args, &block).order_by_key
end
auto(*args) click to toggle source

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

d = Dictionary.auto
d["a"]["b"]["c"] = "abc"  #=> { "a"=>{"b"=>{"c"=>"abc"}}}
# File lib/hashery/dictionary.rb, line 106
def auto(*args)
  #AutoDictionary.new(*args)
  leet = lambda { |hsh, key| hsh[key] = new(&leet) }
  new(*args, &leet)
end
new(*args, &blk) click to toggle source

New Dictiionary.

# File lib/hashery/dictionary.rb, line 115
def initialize(*args, &blk)
  @order = []
  @order_by = nil
  if blk
    dict = self                                  # This ensure autmatic key entry effect the
    oblk = lambda{ |hsh, key| blk[dict,key] }    # dictionary rather then just the interal hash.
    @hash = Hash.new(*args, &oblk)
  else
    @hash = Hash.new(*args)
  end
end
new_by(*args, &blk) click to toggle source

Like new but the block sets the order.

# File lib/hashery/dictionary.rb, line 81
def new_by(*args, &blk)
  new(*args).order_by(&blk)
end

Public Instance Methods

<<(kv) click to toggle source
# File lib/hashery/dictionary.rb, line 318
def <<(kv)
  push(*kv)
end
==(hsh2) click to toggle source

def ==( hsh2 )

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

end

# File lib/hashery/dictionary.rb, line 192
def ==(hsh2)
  if hsh2.is_a?( Dictionary )
    @order == hsh2.order &&
    @hash  == hsh2.instance_variable_get("@hash")
  else
    false
  end
end
[](k) click to toggle source
# File lib/hashery/dictionary.rb, line 201
def [] k
  @hash[ k ]
end
[]=(k, i=nil, v=nil) click to toggle source

Store operator.

h[key] = value

Or with additional index.

h[key,index] = value
# File lib/hashery/dictionary.rb, line 217
def []=(k, i=nil, v=nil)
  if v
    insert(i,k,v)
  else
    store(k,i)
  end
end
clear() click to toggle source
# File lib/hashery/dictionary.rb, line 235
def clear
  @order = []
  @hash.clear
end
delete( key ) click to toggle source
# File lib/hashery/dictionary.rb, line 240
def delete( key )
  @order.delete( key )
  @hash.delete( key )
end
delete_if() click to toggle source
# File lib/hashery/dictionary.rb, line 261
def delete_if
  order.clone.each { |k| delete k if yield(k,@hash[k]) }
  self
end
dup() click to toggle source
# File lib/hashery/dictionary.rb, line 343
def dup
  a = []
  each{ |k,v| a << k; a << v }
  self.class[*a]
end
each() click to toggle source
# File lib/hashery/dictionary.rb, line 255
def each
  order.each { |k| yield( k,@hash[k] ) }
  self
end
Also aliased as: each_pair
each_key() click to toggle source
# File lib/hashery/dictionary.rb, line 245
def each_key
  order.each { |k| yield( k ) }
  self
end
each_pair() click to toggle source
Alias for: each
each_value() click to toggle source
# File lib/hashery/dictionary.rb, line 250
def each_value
  order.each { |k| yield( @hash[k] ) }
  self
end
empty?() click to toggle source
# File lib/hashery/dictionary.rb, line 392
def empty?
  @hash.empty?
end
fetch(k, *a, &b) click to toggle source
# File lib/hashery/dictionary.rb, line 205
def fetch(k, *a, &b)
  @hash.fetch(k, *a, &b)
end
first(x=nil) click to toggle source
# File lib/hashery/dictionary.rb, line 376
def first(x=nil)
  return @hash[order.first] unless x
  order.first(x).collect { |k| @hash[k] }
end
has_key?(key) click to toggle source
# File lib/hashery/dictionary.rb, line 396
def has_key?(key)
  @hash.has_key?(key)
end
insert( i,k,v ) click to toggle source
# File lib/hashery/dictionary.rb, line 225
def insert( i,k,v )
  @order.insert( i,k )
  @hash.store( k,v )
end
inspect() click to toggle source
# File lib/hashery/dictionary.rb, line 337
def inspect
  ary = []
  each {|k,v| ary << k.inspect + "=>" + v.inspect}
  '{' + ary.join(", ") + '}'
end
invert() click to toggle source
# File lib/hashery/dictionary.rb, line 276
def invert
  hsh2 = self.class.new
  order.each { |k| hsh2[@hash[k]] = k }
  hsh2
end
key?(key) click to toggle source
# File lib/hashery/dictionary.rb, line 400
def key?(key)
  @hash.key?(key)
end
keys() click to toggle source
# File lib/hashery/dictionary.rb, line 272
def keys
  order
end
last(x=nil) click to toggle source
# File lib/hashery/dictionary.rb, line 382
def last(x=nil)
  return @hash[order.last] unless x
  order.last(x).collect { |k| @hash[k] }
end
length() click to toggle source
# File lib/hashery/dictionary.rb, line 387
def length
  @order.length
end
Also aliased as: size
merge( hsh2 ) click to toggle source
# File lib/hashery/dictionary.rb, line 356
def merge( hsh2 )
  self.dup.update(hsh2)
end
merge!( hsh2 ) click to toggle source
Alias for: update
order() click to toggle source
# File lib/hashery/dictionary.rb, line 127
def order
  reorder if @order_by
  @order
end
order_by( &block ) click to toggle source

Keep dictionary sorted by a specific sort order.

# File lib/hashery/dictionary.rb, line 134
def order_by( &block )
  @order_by = block
  order
  self
end
order_by_key() click to toggle source

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.

# File lib/hashery/dictionary.rb, line 154
def order_by_key
  @order_by = lambda { |k,v| k }
  order
  self
end
order_by_value() click to toggle source

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 }
# File lib/hashery/dictionary.rb, line 172
def order_by_value
  @order_by = lambda { |k,v| v }
  order
  self
end
pop() click to toggle source
# File lib/hashery/dictionary.rb, line 332
def pop
  key = order.last
  key ? [key,delete(key)] : nil
end
push( k,v ) click to toggle source
# File lib/hashery/dictionary.rb, line 322
def push( k,v )
  unless @hash.include?( k )
    @order.push( k )
    @hash.store( k,v )
    true
  else
    false
  end
end
reject(&block) click to toggle source
# File lib/hashery/dictionary.rb, line 282
def reject(&block)
  self.dup.delete_if(&block)
end
reject!( &block ) click to toggle source
# File lib/hashery/dictionary.rb, line 286
def reject!( &block )
  hsh2 = reject(&block)
  self == hsh2 ? nil : hsh2
end
reorder() click to toggle source
# File lib/hashery/dictionary.rb, line 179
def reorder
  if @order_by
    assoc = @order.collect{ |k| [k,@hash[k]] }.sort_by(&@order_by)
    @order = assoc.collect{ |k,v| k }
  end
  @order
end
replace(hsh2) click to toggle source
# File lib/hashery/dictionary.rb, line 291
def replace(hsh2)
  case hsh2
  when Hash
    @order = hsh2.keys
    @hash  = hsh2
  else
    @order = hsh2.order
    @hash  = hsh2.hash
  end
  reorder
end
reverse() click to toggle source
# File lib/hashery/dictionary.rb, line 371
def reverse
  dup.reverse!
end
reverse!() click to toggle source
# File lib/hashery/dictionary.rb, line 366
def reverse!
  @order.reverse!
  self
end
select() click to toggle source
# File lib/hashery/dictionary.rb, line 360
def select
  ary = []
  each { |k,v| ary << [k,v] if yield k,v }
  ary
end
shift() click to toggle source
# File lib/hashery/dictionary.rb, line 303
def shift
  key = order.first
  key ? [key,delete(key)] : super
end
size() click to toggle source
Alias for: length
store( a,b ) click to toggle source
# File lib/hashery/dictionary.rb, line 230
def store( a,b )
  @order.push( a ) unless @hash.has_key?( a )
  @hash.store( a,b )
end
to_a() click to toggle source
# File lib/hashery/dictionary.rb, line 404
def to_a
  ary = []
  each { |k,v| ary << [k,v] }
  ary
end
to_h() click to toggle source
# File lib/hashery/dictionary.rb, line 418
def to_h
  @hash.dup
end
to_hash() click to toggle source
# File lib/hashery/dictionary.rb, line 414
def to_hash
  @hash.dup
end
to_s() click to toggle source
# File lib/hashery/dictionary.rb, line 410
def to_s
  self.to_a.to_s
end
unshift( k,v ) click to toggle source
# File lib/hashery/dictionary.rb, line 308
def unshift( k,v )
  unless @hash.include?( k )
    @order.unshift( k )
    @hash.store( k,v )
    true
  else
    false
  end
end
update( hsh2 ) click to toggle source
# File lib/hashery/dictionary.rb, line 349
def update( hsh2 )
  hsh2.each { |k,v| self[k] = v }
  reorder
  self
end
Also aliased as: merge!
values() click to toggle source
# File lib/hashery/dictionary.rb, line 266
def values
  ary = []
  order.each { |k| ary.push @hash[k] }
  ary
end

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