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.
Using a Dictionary is almost the same as using a 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
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.
Dictionary is a port of OrderHash 2.0 Copyright © 2005 Jan Molic.
People who have contributed to this class since then include:
Andrew Johnson (merge, #to_a, inspect, shift and Hash[])
Jeff Sharpe (reverse and reverse!)
Thomas Leitner (has_key? and key?)
OrderedHash is public domain.
# File lib/hashery/dictionary.rb, line 63 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
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
Alternate to new which auto-creates sub-dictionaries as needed.
Examples
d = Dictionary.auto d["a"]["b"]["c"] = "abc" #=> { "a"=>{"b"=>{"c"=>"abc"}}}
# File lib/hashery/dictionary.rb, line 109 def auto(*args) #AutoDictionary.new(*args) leet = lambda { |hsh, key| hsh[key] = new(&leet) } new(*args, &leet) end
New Dictiionary.
# File lib/hashery/dictionary.rb, line 119 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
Like new but the block sets the order.
# File lib/hashery/dictionary.rb, line 80 def new_by(*args, &blk) new(*args).order_by(&blk) end
Same as push.
# File lib/hashery/dictionary.rb, line 424 def <<(kv) push(*kv) end
Is the dictionary instance equivalent to another?
# File lib/hashery/dictionary.rb, line 215 def ==(hsh2) if hsh2.is_a?( Dictionary ) @order == hsh2.order && @hash == hsh2.instance_variable_get("@hash") else false end end
Lookup entry with key.
# File lib/hashery/dictionary.rb, line 227 def [] key @hash[ key ] end
Store operator.
h[key] = value
Or with additional index.
h[key,index] = value
# File lib/hashery/dictionary.rb, line 247 def []=(k, i=nil, v=nil) if v insert(i,k,v) else store(k,i) end end
Clear dictionary of all entries.
# File lib/hashery/dictionary.rb, line 282 def clear @order = [] @hash.clear end
Delete the entry with given key
.
# File lib/hashery/dictionary.rb, line 290 def delete(key) @order.delete(key) @hash.delete(key) end
Delete entry if it fits conditional block.
# File lib/hashery/dictionary.rb, line 324 def delete_if order.clone.each { |k| delete k if yield(k,@hash[k]) } self end
Duplicate dictionary.
Returns [Dictionary].
# File lib/hashery/dictionary.rb, line 465 def dup a = [] each{ |k,v| a << k; a << v } self.class[*a] end
Iterate over each key-value pair.
# File lib/hashery/dictionary.rb, line 314 def each order.each { |k| yield( k,@hash[k] ) } self end
Iterate over each key.
# File lib/hashery/dictionary.rb, line 298 def each_key order.each { |k| yield( k ) } self end
Iterate over each value.
# File lib/hashery/dictionary.rb, line 306 def each_value order.each { |k| yield( @hash[k] ) } self end
Is the dictionary empty?
Returns `true` or `false`.
# File lib/hashery/dictionary.rb, line 553 def empty? @hash.empty? end
Featch entry given key
.
# File lib/hashery/dictionary.rb, line 234 def fetch(key, *a, &b) @hash.fetch(key, *a, &b) end
Get/set initial entry value.
# File lib/hashery/dictionary.rb, line 526 def first(x=nil) return @hash[order.first] unless x order.first(x).collect { |k| @hash[k] } end
Does the dictionary have a given key
.
Returns `true` or `false`.
# File lib/hashery/dictionary.rb, line 562 def has_key?(key) @hash.has_key?(key) end
Insert entry into dictionary at specific index position.
index - [Integer] Position of order placement. key - [Object] Key to associate with value. value - [Object] Value to associate with key.
Returns `value` stored.
# File lib/hashery/dictionary.rb, line 264 def insert(index, key, value) @order.insert(index, key) @hash.store(key, value) end
Inspection string for Dictionary.
Returns [String].
# File lib/hashery/dictionary.rb, line 454 def inspect ary = [] each {|k,v| ary << k.inspect + "=>" + v.inspect} '{' + ary.join(", ") + '}' end
Invert the dictionary.
Returns [Dictionary] New dictionary that is inverse of the original.
# File lib/hashery/dictionary.rb, line 354 def invert hsh2 = self.class.new order.each { |k| hsh2[@hash[k]] = k } hsh2 end
Does the dictionary have a given key
.
Returns `true` or `false`.
# File lib/hashery/dictionary.rb, line 571 def key?(key) @hash.key?(key) end
List of all dictionary keys.
Returns [Array].
# File lib/hashery/dictionary.rb, line 345 def keys order end
Get/set last entry value.
# File lib/hashery/dictionary.rb, line 534 def last(x=nil) return @hash[order.last] unless x order.last(x).collect { |k| @hash[k] } end
Number of items in the dictionary.
# File lib/hashery/dictionary.rb, line 542 def length @order.length end
Merge other hash creating new dictionary.
Returns [Dictionary].
# File lib/hashery/dictionary.rb, line 489 def merge(hsh2) self.dup.update(hsh2) end
Order of keys.
Returns [Array].
# File lib/hashery/dictionary.rb, line 136 def order reorder if @order_by @order end
Keep dictionary sorted by a specific sort order.
block - Ordering procedure.
Returns self
.
# File lib/hashery/dictionary.rb, line 148 def order_by( &block ) @order_by = block order self end
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.
Returns self
.
# File lib/hashery/dictionary.rb, line 171 def order_by_key @order_by = Proc.new{ |k,v| k } order self end
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 190 def order_by_value @order_by = Proc.new{ |k,v| v } order self end
Pop entry off the bottom of dictionary.
# File lib/hashery/dictionary.rb, line 444 def pop key = order.last key ? [key,delete(key)] : nil end
Push entry on to bottom of the dictionary.
# File lib/hashery/dictionary.rb, line 431 def push(k,v) unless @hash.include?( k ) @order.push( k ) @hash.store( k,v ) true else false end end
Reject entries based on give condition block and return new dictionary.
Returns [Dictionary].
# File lib/hashery/dictionary.rb, line 366 def reject(&block) self.dup.delete_if(&block) end
Reject entries based on give condition block.
Returns [Hash] of rejected entries.
FIXME: This looks like it is implemented wrong!!!
# File lib/hashery/dictionary.rb, line 377 def reject!( &block ) hsh2 = reject(&block) self == hsh2 ? nil : hsh2 end
Re-apply the sorting procedure.
# File lib/hashery/dictionary.rb, line 199 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 dictionary entries with new table.
# File lib/hashery/dictionary.rb, line 385 def replace(hsh2) case hsh2 when Dictionary @order = hsh2.order @hash = hsh2.to_h when Hash @hash = hsh2 @order = @hash.keys else @hash = hsh2.to_h @order = @hash.keys end reorder end
Reverse the order of duplicte dictionary.
Returns [Dictionary].
# File lib/hashery/dictionary.rb, line 519 def reverse dup.reverse! end
Reverse the order of the dictionary.
Returns self.
# File lib/hashery/dictionary.rb, line 509 def reverse! @order.reverse! self end
Select items from dictiornary.
Returns [Array] of two-element arrays.
# File lib/hashery/dictionary.rb, line 498 def select ary = [] each { |k,v| ary << [k,v] if yield k,v } ary end
Remove entry from the to top of dictionary.
# File lib/hashery/dictionary.rb, line 403 def shift key = order.first key ? [key,delete(key)] : super end
Add entry into dictionary.
Returns `value`.
# File lib/hashery/dictionary.rb, line 274 def store(key, value) @order.push(key) unless @hash.has_key?(key) @hash.store(key, value) end
Convert to array.
Returns [Array] of two-element arrays.
# File lib/hashery/dictionary.rb, line 580 def to_a ary = [] each { |k,v| ary << [k,v] } ary end
Get a duplicate of the underlying hash table.
Returns [Hash].
# File lib/hashery/dictionary.rb, line 609 def to_h @hash.dup end
Get a duplicate of the underlying hash table.
Returns [Hash].
# File lib/hashery/dictionary.rb, line 600 def to_hash @hash.dup end
Convert to array then to string.
Returns [String].
# File lib/hashery/dictionary.rb, line 591 def to_s self.to_a.to_s end
Push entry on to the top of dictionary.
# File lib/hashery/dictionary.rb, line 411 def unshift( k,v ) unless @hash.include?( k ) @order.unshift( k ) @hash.store( k,v ) true else false end end
Update dictionary with other hash.
Returns self.
# File lib/hashery/dictionary.rb, line 476 def update( hsh2 ) hsh2.each { |k,v| self[k] = v } reorder self end
List of all dictionary values.
Returns [Array].
# File lib/hashery/dictionary.rb, line 334 def values ary = [] order.each { |k| ary.push @hash[k] } ary end
Underlying hash table.
# File lib/hashery/dictionary.rb, line 618 def hash_table @hash end