modelA.name = "abc"
modelB.name = "efg"
modelC.name = "hij"
modelD.name = "abc"
modelE.name = "efg"

struct Model {
    var name: String?
}

let allModelsArray = [Model(name: "abc"), Model(name: "efg"), Model(name: "hij"), Model(name: "abc"), Model(name: "efg"), Model(name: "efg"), Model(name: "hij")]

let abcModelsArray = allModelsArray.filter { $0.name == "abc" }
// [Model(name: Optional("abc")), Model(name: Optional("abc"))]

let hijModelsArray = allModelsArray.filter { $0.name == "hij" }
// [Model(name: Optional("hij")), Model(name: Optional("hij"))]

struct Model {
    var type : String
    var name : String
}
var modelA = Model(type: "A", name: "abc")
var modelB = Model(type: "B", name: "efg")
var modelC = Model(type: "C", name: "abc")
var modelD = Model(type: "D", name: "efg")

let models = [modelA,modelB,modelC,modelD]

let names = Set(models.map({return $0.name}))

var groupedModels : [String:[Model]] = [:]
for var name in names {
    let elements = models.filter({$0.name == name})
    groupedModels[name] = elements
}

let a = [modelA, modelB, modelC, modelD, modelE]

let arr = a.reduce([:]) { (result, currentModel) -> [String: [Model]] in
    var mutableDic = result
    if ((mutableDic[currentModel.name]) != nil) {
        mutableDic[currentModel.name]?.append(currentModel)
    } else {
        mutableDic[currentModel.name] = [currentModel]
    }

    return mutableDic
}

var mutableDic = [String : [Model]]()

        for aModel in a {
            if ((mutableDic[aModel.name]) != nil) {
                mutableDic[aModel.name]?.append(aModel)
            } else {
                mutableDic[aModel.name] = [aModel]
            }
        }

var d[String: [Model]]
for i in array {
    if d[i.name] == nil { // Don't repeat if already found
        let m = array.filter { $0.name == i.name }
        if m.count > 1 {
            d[i.name] = m
        }
    }
}