Calculate of prices in within an array of strings Array<String>

Question

I have an array that describes a list of auto parts (Swift/IOS,array already in such structure arrived from other source.):

let parts = [
    "Wheel = 230$",
    "Door = 200$",
    "Wheel = 300$",
    "Seat = 150$",
    "Seat = 150$",
    "Rugs = 100$"]

I need to calculate the sum of the prices of the auto parts for each type of part. Here's the result I'm looking for:

let expectedResult = [
    "wheel 530$",
    "Door 200$",
    "Seat 300$",
    "Rugs 100$"
]

I don’t understand how to do it.

Answer 1

Here is a solution where I loop through the array and split each element on "=" and then sum the values together using a dictionary. Once that is done the dictionary is converted back to an array

let parts = [
    "Wheel = 230$",
    "Door = 200$",
    "Wheel = 300$",
    "Seat = 150$",
    "Seat = 150$",
    "Rugs = 100$"]

var values = [String: Int]() // Used to calculate totals per part

parts.forEach { string in
    let split = string.split(separator: "=")

    // Make sure the split worked as expected and that we have an integer value after the =
    guard split.count == 2,
          let value = Int(String(split[1]).trimmingCharacters(in: .whitespaces).dropLast()) else { return }

    let key = String(split[0]).trimmingCharacters(in: .whitespaces)

    // Sum values over the part name
    values[key, default: 0] += value
}

// Convert back to an array of strings
let output = values.map { "\($0.key) \($0.value)$"}

print(output)