ChuckArrayBasedOnProperty.swift

struct T {
	let s: String
	let v: Int
}

let a = [T(s: "abc", v: 0), T(s: "abc", v: 1), T(s: "def", v: 0)]

let b = Array(a.reduce([Int: [T]]()) { (d, a) -> [Int: [T]] in
	var d = d
	let t = a.v
	d[t] = d[t] == nil ? [a] : d[t]! + [a]
	return d
}.values) // b = [[T(s: "abc", v: 0), T(s: "def", v: 0)], [T(s: "abc", v: 1)]]

// As an extension

extension Collection {
    func sortAndChuck<C: Hashable>(keyPath: KeyPath<Element, C>) -> [[Element]] {
        return Array(self.reduce([C: [Element]]()) { (d, a) -> [C: [Element]] in
            var d = d
            let t = a[keyPath: keyPath]
            d[t] = d[t] == nil ? [a] : d[t]! + [a]
            return d
        }.values)
    }
    
    func sortAndChuck2<C: Hashable>(keyPath: KeyPath<Element, C>) -> [[Element]] {
        var ret: [[Element]] = []
        var _v: [C] = []
        for t in self {
            let _tempV = t[keyPath: keyPath]
            if let i = _v.firstIndex(of: _tempV) {
                ret[i].append(t)
            } else {
                let i: Int = ret.count
                _v.append(_tempV)    // keep index in `_indexRet`
                ret.insert([], at: i)       // init new Array
                ret[i].append(t)
            }
        }
        return ret
    }
}

// Usage :
let _ = a.sortAndChuck(keyPath: \T.v)