Combine / Merge Multiple Arrays Into One - arrays

Question

I have four list of arrays:
var products: [Product] = []
var addressInfo: [AddressInfo] = []
var favorites: [Favorite] = []
var amounts: [Amount] = []
I want to combine them all into one so I have only one variable:
var combined = [Product/AddressInfo/Favorite/Amount]()
How would I go about merging them into one array var cobmbined = [Combined]() ?
This these are two examples of how my structs look like:
struct Amount {
var amountsDeliveryCharge: Double
var amountsDriverTip: Double
init(
amountsDeliveryCharge: Double,
amountsDriverTip: Double
){
self.amountsDeliveryCharge = amountsDeliveryCharge
self.amountsDriverTip = amountsDriverTip
}
init(data: [String: Any]){
amountsDeliveryCharge = data[DatabaseRef.deliveryCharge] as? Double ?? 0.0
amountsDriverTip = data[DatabaseRef.driverTip] as? Double ?? 0.0
}
static func modelToData(amount: Amount) -> [String: Any] {
let data : [String: Any] = [
DatabaseRef.deliveryCharge : amount.amountsDeliveryCharge,
DatabaseRef.driverTip : amount.amountsDriverTip
]
return data
}
}
This is the other struct:
struct Product {
var price: Double
var priceUnit: String
init(
price: Double,
priceUnit: String
){
self.price = price
self.priceUnit = priceUnit
}
init(data: [String: Any]){
price = data[DatabaseRef.price] as? Double ?? 0.0
priceUnit = data[DatabaseRef.priceUnit] as? String ?? ""
}
static func modelToData(product: Product) -> [String: Any] {
let data : [String: Any] = [
DatabaseRef.price : product.price,
DatabaseRef.priceUnit : product.priceUnit
]
return data
}
}
The other two structs look similar in structure as well.

Answer 1

Assuming the ordering is the same in each of them, create a struct with the appropriate properties
struct Combined {
let product: Product
let addressInfo: AddressInfo
let favourite: Favourite
let amount: Amount
}
and then either loop through the arrays using a counter to index then and create instances using the memberWise initialiser, or use a static factory function to make and return the array:
static func makeFrom(products: [Product], addresses: [AddressInfo], favourites: [Favourite], amounts: [Amount]) -> [Combined] {
guard products.count == addresses.count, addresses.count == favourites.count, favourites.count == amounts.count else {fatalError()}. //handle better in practice
var combined = [Combined]()
for index in 0..<products.count {
combined.append(Combined(product: products[index],
addressInfo: addresses[index],
favourite: favourites[index],
amount: amounts[index])
}
return combined
}
The above checks that all arrays are teh same length and if not calls fatalError(). In reality you'd want to handle the error better than this.
Then use as:
let combined = Combined.makeFrom(products: products, addresses:addressInfo, favourites: favourites, amounts: amounts)

Answer 2

You can cast your arrays as [Any] and add them.
let combinedVals = (products as [Any]) + (addressInfo as [Any]) + (favorites as [Any]) + (amounts as [Any])
Alternatively you can create a protocol and have your structs adhere to it.
protocol Combined {
}
struct Amount: Combined {
var amountsDeliveryCharge: Double
var amountsDriverTip: Double
}
struct Product: Combined {
var price: Double
var priceUnit: String
}
let combinedValues: [Combined] = amounts + products
When you iterate over the array, if you need to check what it is, you can use a switch to check it's type.
combinedValues.forEach { (value) in
switch value {
case let value as Amount:
print(value.amountsDriverTip)
break
case let value as Product:
print(value.price)
break
default:
break
}
}