Finding closest value in array of custom objects in swift

Question

Hi I do have array of custom objects in swift, like below

Objects of below class

Class Person {
  let name: String
  let pointsEarned: CGFloat
}

Array is like below


let person1 = Person(“name1”, “5.6”)

let person2 = Person(“name2”, “6.6”)

let person3 = Person(“name3”, “1.6”)

let persons = [person1, person2, person3 ]

I would like find person who’s earned points are close to 7.0

Is there extension on array I can write for this?

Appreciate any help! Thanks.

Distance from 7 is just abs(7 - pointsEarned), so sort the objects by whichever has the lowest distence — Alexander
– Alexander, Commented Apr 19, 2020 at 1:40
You are using sort, and then it's people.sort{ insideClosure }.first while it could just be people.min(by: { insideClosure } — Larme
– Larme, Commented Apr 19, 2020 at 16:24

Alexander · Accepted Answer · 2020-04-19 15:04:08Z

1

Sort your objects by their distance from the goal (7), computed asabs(goal - score)`:

people.sort { abs(7 - $0.score) < abs(7 - $1.score) }

answered Apr 19, 2020 at 15:04

Alexander

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Comments

user652038 · Accepted Answer · 2020-04-19 16:14:24Z

1

Alexander's answer is good, but you only need the min.

public extension Sequence {
  func min<Comparable: Swift.Comparable>(
    by getComparable: (Element) throws -> Comparable
  ) rethrows -> Element? {
    try self.min {
      try getComparable($0) < getComparable($1)
    }
  }
}

I also think abs as a global function looks archaic. magnitude is the same value.

persons.min { ($0.pointsEarned - 7).magnitude }

You can use the argument label with a trailing closure if you want:

persons.min(by:) { ($0.pointsEarned - 7).magnitude }

answered Apr 19, 2020 at 16:14

user652038

1 Comment

Alexander Over a year ago

Woah, didn't know about magnitude. That's so much better!

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