Find closest item in array of objects? - arrays

Question

When I have a reference to an item in an array, I'd like to find another item closest to it that matches a certain criteria.
For example, I have this array:
struct Person {
var name = ""
var age = ""
var gender = ""
var address = ""
}
let array = [Person(name:"ahmad",age:"22",gender:"male",address:"USA"),
Person(name:"ahmad",age:"23",gender:"male",address:"KSA")]
Now let's say I have an object as:
let object = Person(name:"ahmad",age:"25",gender:"male",address:"USA")
based on that, I need to find the closest person to it on array, based on the values of all its properties.
As an example, based on my above code, the closest object in array to object is the first one because they have the same name, gender and address (3 matched properties), instead of the second one because there is only 2 matched properties.

Answer 1

First you have to define a function which measures the “closeness”
of two persons. Based on your example that could be
struct Person {
let name: String
let age: String
let gender: String
let address: String
// Compute a number measuring the “closeness” to another person,
// with smaller numbers meaning “closer”.
// For example: the number of non-matching properties.
func distance(to other: Person) -> Int {
return (name == other.name ? 0 : 1)
+ (age == other.age ? 0 : 1)
+ (gender == other.gender ? 0 : 1)
+ (address == other.address ? 0 : 1)
}
}
Then the closest person can be determined using min(by:):
let object = Person(name:"ahmad", age:"25", gender:"male", address:"USA")
let closest = array.min(by: { $0.distance(to: object) < $1.distance(to: object) })!
print(closest) // Person(name: "ahmad", age: "22", gender: "male", address: "USA")
The above distance method is just an example, you have to adjust it
for your exact needs.