Add two maps in Groovy while summing up values for common keys

Question

I have two maps in Groovy [a: 1, b: 2] and [b:1, c:3] and would like to create from them a third map [a: 1, b: 3, c: 3]. Is there a Gr

Answer 1

This does it:

Map additionJoin( Map map1, Map map2 )
{
  def result = [:];
  result.putAll( map1 );
  result.putAll( map2 );

  result.each { key, value ->
    if( map1[key] && map2[key] )
    {
      result[key] = map1[key] + map2[key]
    }
  }

  return result;
}

def a = [a: 1, b: 2]
def b = [b:1,c:3]

def c = additionJoin( a, b )

println c