In which area or structure is a data array usually stored?

In iOS, data arrays are usually stored in data structures such as Array or NSMutableArray (in Objective-C). If you need to store an array for a long time, you can save it in:

• UserDefaults — for small and simple data.
• File system — for example, serialize the array into JSON or plist and write it to a file.
• Core Data — if the data is complex and requires management of relationships and queries.

Example of saving an array in UserDefaults:

let fruits = ["Apple", "Banana", "Orange"]
UserDefaults.standard.set(fruits, forKey: "fruitsArray")

// Reading
if let savedFruits = UserDefaults.standard.array(forKey: "fruitsArray") as? [String] {
    print(savedFruits)
}