Groovy merge two lists?

Question

I have two lists:

listA: 
[[Name: mr good, note: good,rating:9], [Name: mr bad, note: bad, rating:5]] 

listB: 
[[Name: mr good, note: good,score:77], [Name: mr bad, note: bad, score:12]]

I want to get this one

listC:
[[Name: mr good, note: good,, rating:9, score:77], [Name: mr bad, note: bad, rating:5,score:12]] 

how could I do it ?

thanks.

Answer 1

collect all elements in listA, and find the elementA equivilient in listB. Remove it from listB, and return the combined element.

If we say your structure is the above, I would probably do:

def listC = listA.collect( { elementA ->
    elementB = listB.find { it.Name == elementA.Name }

    // Remove matched element from listB
    listB.remove(elementB)
    // if elementB == null, I use safe reference and elvis-operator
    // This map is the next element in the collect
    [
        Name: it.Name,
        note: "${it.note} ${elementB?.note :? ''}", // Perhaps combine the two notes?
        rating: it.rating?:0 + elementB?.rating ?: 0, // Perhaps add the ratings?
        score: it.score?:0 + elementB?.score ?: 0 // Perhaps add the scores?
    ] // Combine elementA + elementB anyway you like
}

// Take unmatched elements in listB and add them to listC
listC += listB