I'm learning swift, and I do the sololearn course to get some knowledge, but I bumped into something that I don't understand.
It is about modifying an array's values. The questionable part states the following:
In the following example, the elements with index 1, 2, 3 are replaced with two new values.
shoppingList[1...3] = [“Bananas”, “Oranges”]
How can an one dimensional array take more than one value per index? And how do I access them? Am I misunderstanding something?
What this code does is replacing the element of shoppingList in the 1...3 range using Array.subscript(_:)
That means considering this array:
var shoppingList = ["Apples", "Strawberries", "Pears", "Pineaples"]
that with:
shoppingList[1...3] = ["Bananas", "Oranges"]
Strawberries, Pears and Pineaples will be replaced by Bananas and Oranges.
so the resulting array will be: Apples, Bananas, Oranges
When you assign to a range of indices in an array (array[1...3]), those elements are removed from the array and the new elements are 'slotted in' in their place. This can result in the array growing or shrinking.
var array = Array(0...5)
// [0, 1, 2, 3, 4, 5]
array[1...3] = [-1, -2]
// [0, -1, -2, 3, 4]
Notice how our array's length is now one element shorter.
You could use a tuple (Value, Value), or create a struct to handle your values there, in fact if you plan to reuse this pair or value, a struct is the way to go.
By the way, there's no need to add [1..3], just put the values inside the brackets.
struct Value {
var name: String
var lastName: String
}
let values = [Value(name: "Mary", lastName: "Queen"), Value(name: "John", lastName: "Black")]
// Access to properties
let lastName = values[1].lastName
// OR
let tuples = [("Mary", "Queen"), ("John", "Black")]
let lastNameTuple = tuples[1].1
Hope you're enjoying Swift!
replaceSubrangemethod where you replace any number of elements with another collection.