Sorting an array of arrays in swift 3 - arrays

Question

var myArray: [[String]] =
[
["1", "picture1.png", "John", "Smith"],
["2", "picture2.png", "Mike", "Rutherford"],
]
How to sort myArray on first item ? second item ? ascending ? descending ?
Many Thanks

Answer 1

I would suggest you create a struct or class to package this related data together:
struct Person {
let id: Int
let picture: String // This should probably be a URL, NSImage or UIImage
let firstName: String
let lastName: String
}
And then define your instances with the correct types (e.g. the id is an Int, not a String representation of an Int.
let people = [
Person(
id: 1,
picture: "picture1.png",
firstName: "John",
lastName: "Smith"
),
Person(
id: 2,
picture: "picture2.png",
firstName: "Mike",
lastName: "Rutherford"
),
]
From there, you can sort it any which way you please:
people.sorted{ $0.id < $1.id }
people.sorted{ $0.id > $1.id }
people.sorted{ $0.picture < $1.picture }
people.sorted{ $0.picture > $1.picture }
people.sorted{ $0.firstName < $1.firstName }
people.sorted{ $0.firstName > $1.firstName }
people.sorted{ $0.lastName < $1.lastName }
people.sorted{ $0.lastName > $1.lastName }

Answer 2

Notice, that index ranged is not checked, what could lead to a fatal error at runtime. Check Alexanders comment! :)
var myArray: [[String]] =
[
["1", "picture1.png", "John", "Smith"],
["2", "picture2.png", "Mike", "Rutherford"],
]
func sort<T: Comparable>(ArrayOfArrays: [[T]], sortingIndex: Int, sortFunc: (T, T) -> Bool)) -> [[T]] {
return ArrayOfArrays.sorted {sortFunc($0[sortingIndex], $1[sortingIndex])}
}
}
print(sort(ArrayOfArrays: myArray, sortingIndex: 0, sortFunc: <))
//[["1", "picture1.png", "John", "Smith"], ["2", "picture2.png", "Mike", "Rutherford"]]
print(sort(ArrayOfArrays: myArray, sortingIndex: 0, sortFunc: >))
//[["2", "picture2.png", "Mike", "Rutherford"], ["1", "picture1.png", "John", "Smith"]]

Answer 3

Swift's Array has a built-in sort function. Just call it.
myArray[0].sort { $0.compare($1, options: .numeric) == .orderedAscending }
myArray[1].sort { $0.compare($1, options: .numeric) == .orderedDescending }

Answer 4

To sort the arrays using numeric string comparison (e.g. where "2" < "10") of the item at a particular index:
let index = 1 // sort by second entry
myArray.sort { $0[index].compare($1[index], options: .numeric) == .orderedAscending }
If you don't need numeric comparisons (e.g. where "10" < "2"):
myArray.sort { $0[index] < $1[index] }
As others point out, though, you really should be using arrays of custom struct or class rather than representing your objects as mere array of strings.