浅谈SwiftUI 里面$0是什么意思如何用

import UIKit

let name = [1,2,3,9,8,6]
let reverseName = name.sorted(by:{$0>$1})
let reverseName2 = name.sorted(by:{$1>$0})
print(name)
print(reverseName)
print(reverseName2)

let numbers = [1,2,5,4,3,6,8,7]
    sortNumbers = numbers.sorted(by: { (a, b) -> Bool in
      return a < b
    })
    print("numbers -" + "\(sortNumbers)")

let numbers = [1,2,5,4,3,6,8,7]
 var sortNumbers = numbers.sorted(by: {$0 < $1})
 print("numbers -" + "\(sortNumbers)")