How to compare elements of two arrays

Question

I want to compare the elements of two arrays and check if they are equal. I already tried various solutions but nothing really works.

I tried the solution from How to compare two array of objects?

This is my object:

struct AccountBalance: Decodable {
    let balance: Double
    let currency: String

    init(balance: Double, currency: String ) {
        self.currency = currency
        self.balance = balance
    }

    enum CodingKeys: String, CodingKey {
        case currency = "Currency"
        case balance = "Balance"
    }
}

This is the code from the link I tried:

let result = zip(accountBalance, getsSaved).enumerate().filter() {
                $1.0 == $1.1
                }.map{$0.0}

But I get this error:

Closure tuple parameter '(offset: Int, element: (AccountBalance, AccountBalance))' does not support destructuring with implicit parameters

Answer 1

I will suggest you implement the accepted answer of the link you provided because it controls that both arrays are the same size and it orders them.

But if you want that your code works I solved like this:

In order to have control of the comparison your struct should implement the Equatable protocol and overload the operator ==

extension AccountBalance : Equatable {}

func ==(lhs: AccountBalance, rhs: AccountBalance) -> Bool {
    return lhs.balance == rhs.balance && lhs.currency == rhs.currency
}

Then compare both arrays and check if contains false, if it does, one or more items in the array aren't the same.

let result = !zip(accountBalance, getsSaved).enumerated().map() {
    $1.0 == $1.1
}.contains(false)

Hope it helps you

Answer 2

Array provides a function elementsEqual which is able to compare two arrays without explicitly conforming to Equatable:

let result = accountBalance.elementsEqual(getsSaved) {
    $0.balance == $1.balance && $0.currency == $1.currency
}

Edit:

If you want to have the equality result regardless of the order of objects in the array then you can just add sort with each of the arrays.

let result = accountBalance.sorted { $0.balance < $1.balance }.elementsEqual(getsSaved.sorted { $0.balance < $1.balance }) {
    $0.balance == $1.balance && $0.currency == $1.currency
}