How to merge two maps in groovy

Question

Question:
How to merge the maps while summing up values of common keys among the maps.

Input:

[a: 10, b:2, c:         


        

Answer 1

Would this suffice?

Map one = [a:10, b:2, c:3]
Map two = [b:3, c:2, d:5]

Map mergeOn(Map one, Map two, Closure closure) {
  two.inject([:] << one) { acc, key, val ->
    key in acc.keySet() ? acc[key] = closure(acc[key], val) : acc << [(key): val]
    acc
  }
}

assert mergeOn(one, two) { a, b -> a + b }          == [a:10, b:5, c:5, d:5]
assert mergeOn(one, two) { a, b -> a - b }          == [a:10, b:-1, c:1, d:5]
assert mergeOn(one, two) { a, b -> a * b }          == [a:10, b:6, c:6, d:5]
assert mergeOn(one, two) { a, b -> Math.max(a, b) } == [a:10, b:3, c:3, d:5]
assert mergeOn(one, two) { a, b -> Math.min(a, b) } == [a:10, b:2, c:2, d:5]