class TablrSpace::OrderedHash

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 doesn'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

Public Class Methods

[](*args) click to toggle source
# File lib/support/orderedhash.rb, line 88
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/support/orderedhash.rb, line 119
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/support/orderedhash.rb, line 128
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 Dictionary.

# File lib/support/orderedhash.rb, line 136
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/support/orderedhash.rb, line 104
def new_by(*args, &blk)
  new(*args).order_by(&blk)
end

Public Instance Methods

<<(kv) click to toggle source
# File lib/support/orderedhash.rb, line 323
def <<(kv)
  push( *kv )
end
==(hsh2) click to toggle source
# File lib/support/orderedhash.rb, line 205
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/support/orderedhash.rb, line 214
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/support/orderedhash.rb, line 229
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/support/orderedhash.rb, line 247
def clear
  @order = []
  @hash.clear
end
delete( key ) click to toggle source
# File lib/support/orderedhash.rb, line 252
def delete( key )
  @order.delete( key )
  @hash.delete( key )
end
delete_if() { |k,hash| ... } click to toggle source
# File lib/support/orderedhash.rb, line 273
def delete_if
  order.clone.each { |k| delete k if yield(k,@hash[k]) }
  self
end
dup() click to toggle source
# File lib/support/orderedhash.rb, line 348
def dup
  a = []
  each{ |k,v| a << k; a << v }
  self.class[*a]
end
each() { |k,hash| ... } click to toggle source
# File lib/support/orderedhash.rb, line 267
def each
  order.each { |k| yield( k,@hash[k] ) }
  self
end
Also aliased as: each_pair
each_key() { |k| ... } click to toggle source
# File lib/support/orderedhash.rb, line 257
def each_key
  order.each { |k| yield( k ) }
  self
end
each_pair()
Alias for: each
each_value() { |hash| ... } click to toggle source
# File lib/support/orderedhash.rb, line 262
def each_value
  order.each { |k| yield( @hash[k] ) }
  self
end
empty?() click to toggle source
# File lib/support/orderedhash.rb, line 393
def empty?
  @hash.empty?
end
fetch(k, *a, &b) click to toggle source
# File lib/support/orderedhash.rb, line 218
def fetch(k, *a, &b)
  @hash.fetch(k, *a, &b)
end
first() click to toggle source
# File lib/support/orderedhash.rb, line 380
def first
  @hash[order.first]
end
has_key?(key) click to toggle source
# File lib/support/orderedhash.rb, line 397
def has_key?(key)
  @hash.has_key?(key)
end
insert( i,k,v ) click to toggle source
# File lib/support/orderedhash.rb, line 237
def insert( i,k,v )
  @order.insert( i,k )
  @hash.store( k,v )
end
inspect() click to toggle source
# File lib/support/orderedhash.rb, line 342
def inspect
  ary = []
  each {|k,v| ary << k.inspect + "=>" + v.inspect}
  '{' + ary.join(", ") + '}'
end
invert() click to toggle source
# File lib/support/orderedhash.rb, line 288
def invert
  hsh2 = self.class.new
  order.each { |k| hsh2[@hash[k]] = k }
  hsh2
end
key?(key) click to toggle source
# File lib/support/orderedhash.rb, line 401
def key?(key)
  @hash.key?(key)
end
keys() click to toggle source
# File lib/support/orderedhash.rb, line 284
def keys
  order
end
last() click to toggle source
# File lib/support/orderedhash.rb, line 384
def last
  @hash[order.last]
end
length() click to toggle source
# File lib/support/orderedhash.rb, line 388
def length
  @order.length
end
Also aliased as: size
merge( hsh2 ) click to toggle source
# File lib/support/orderedhash.rb, line 361
def merge( hsh2 )
  self.dup.update(hsh2)
end
merge!( hsh2 )
Alias for: update
order() click to toggle source
# File lib/support/orderedhash.rb, line 148
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/support/orderedhash.rb, line 154
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/support/orderedhash.rb, line 173
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/support/orderedhash.rb, line 190
def order_by_value
  @order_by = lambda { |k,v| v }
  order
  self
end
pop() click to toggle source
# File lib/support/orderedhash.rb, line 337
def pop
  key = order.last
  key ? [key,delete(key)] : nil
end
push( k,v ) click to toggle source
# File lib/support/orderedhash.rb, line 327
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/support/orderedhash.rb, line 294
def reject( &block )
  self.dup.delete_if(&block)
end
reject!( &block ) click to toggle source
# File lib/support/orderedhash.rb, line 298
def reject!( &block )
  hsh2 = reject(&block)
  self == hsh2 ? nil : hsh2
end
reorder() click to toggle source
# File lib/support/orderedhash.rb, line 197
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/support/orderedhash.rb, line 303
def replace( hsh2 )
  @order = hsh2.order
  @hash = hsh2.hash
end
reverse() click to toggle source
# File lib/support/orderedhash.rb, line 376
def reverse
  dup.reverse!
end
reverse!() click to toggle source
# File lib/support/orderedhash.rb, line 371
def reverse!
  @order.reverse!
  self
end
select() { |k,v| ... } click to toggle source
# File lib/support/orderedhash.rb, line 365
def select
  ary = []
  each { |k,v| ary << [k,v] if yield k,v }
  ary
end
shift() click to toggle source
Calls superclass method
# File lib/support/orderedhash.rb, line 308
def shift
  key = order.first
  key ? [key,delete(key)] : super
end
size()
Alias for: length
store( a,b ) click to toggle source
# File lib/support/orderedhash.rb, line 242
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/support/orderedhash.rb, line 405
def to_a
  ary = []
  each { |k,v| ary << [k,v] }
  ary
end
to_h() click to toggle source
# File lib/support/orderedhash.rb, line 430
def to_h
  @hash.dup
end
to_hash() click to toggle source
# File lib/support/orderedhash.rb, line 426
def to_hash
  @hash.dup
end
to_json() click to toggle source
# File lib/support/orderedhash.rb, line 411
def to_json
  buf = "["
  map do |k,v|
    buf << k.to_json
    buf << ", "
    buf << v.to_json
  end.join(", ")
  buf << "]"
  buf
end
to_s() click to toggle source
# File lib/support/orderedhash.rb, line 422
def to_s
  self.to_a.to_s
end
unshift( k,v ) click to toggle source
# File lib/support/orderedhash.rb, line 313
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/support/orderedhash.rb, line 354
def update( hsh2 )
  hsh2.each { |k,v| self[k] = v }
  reorder
  self
end
Also aliased as: merge!
values() click to toggle source
# File lib/support/orderedhash.rb, line 278
def values
  ary = []
  order.each { |k| ary.push @hash[k] }
  ary
end