Module: Tins::Subhash

Included in:
Hash
Defined in:
lib/tins/subhash.rb

Instance Method Summary collapse

Instance Method Details

#subhash(*patterns) ⇒ Object

Create a subhash from this hash, that only contains key-value pairs matching patterns and return it. patterns can be for example /^foo/ to put ‘foobar’ and ‘foobaz’ or ‘foo’/:foo to put ‘foo’ into the subhash.

If a block is given this method yields to it after the first pattern matched with a 3-tuple of (key, value, match_data) using the return value of the block as the value of the result hash. match_data is a MatchData instance if the matching pattern was a regular rexpression otherwise it is nil.



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# File 'lib/tins/subhash.rb', line 12

def subhash(*patterns)
  patterns.map! do |pat|
    pat = pat.to_sym.to_s if pat.respond_to?(:to_sym)
    pat.respond_to?(:match) ? pat : pat.to_s
  end
  result =
    if default_proc
      self.class.new(&default_proc)
    else
      self.class.new(default)
    end
  if block_given?
    each do |k, v|
      patterns.each { |pat|
        if pat === k.to_s
          result[k] = yield(k, v, $~)
          break
        end
      }
    end
  else
    each do |k, v|
      result[k] = v if patterns.any? { |pat| pat === k.to_s }
    end
  end
  result
end