class MultiHash

Multi Hash allows you to iterate through multiple hashes at the same time. The values will be an array of values from each hash. If a hash contains no value for the key, it will be nil.

Public Class Methods

new(*hashes) click to toggle source

# File lib/multi_hash_iterator.rb, line 7
def initialize *hashes
  @hashes = hashes
  @memo = {}
end

Public Instance Methods

[](key) click to toggle source

# File lib/multi_hash_iterator.rb, line 41
def [] key
  @memo[key] ||= @hashes.collect { |h| h[key] }
end

each() { |k, v| ... } click to toggle source

Enumerate for each key. Returns an enumerator if block is not present

# File lib/multi_hash_iterator.rb, line 15
def each
  return enum_for(:each) unless block_given?

  # iterate through the memo first
  @memo.each do |k, v|
    yield k, v
  end

  count = @hashes.length
  count.times do |i|
    @hashes[i].each do |key, v|
      next if @memo[key]

      values = [].fill(nil, 0, i)
      values << v
      ((i+1)...count).each do |j|
        values << @hashes[j][key]
      end

      yield key, values if block_given?
      @memo[key] = values
    end
  end
end