Swift Language Arrays Sorting an Array of Strings
Example
3.0
The most simple way is to use sorted():
let words = ["Hello", "Bonjour", "Salute", "Ahola"]
let sortedWords = words.sorted()
print(sortedWords) // ["Ahola", "Bonjour", "Hello", "Salute"]
or sort()
var mutableWords = ["Hello", "Bonjour", "Salute", "Ahola"]
mutableWords.sort()
print(mutableWords) // ["Ahola", "Bonjour", "Hello", "Salute"]
You can pass a closure as an argument for sorting:
let words = ["Hello", "Bonjour", "Salute", "Ahola"]
let sortedWords = words.sorted(isOrderedBefore: { $0 > $1 })
print(sortedWords) // ["Salute", "Hello", "Bonjour", "Ahola"]
Alternative syntax with a trailing closure:
let words = ["Hello", "Bonjour", "Salute", "Ahola"]
let sortedWords = words.sorted() { $0 > $1 }
print(sortedWords) // ["Salute", "Hello", "Bonjour", "Ahola"]
But there will be unexpected results if the elements in the array are not consistent:
let words = ["Hello", "bonjour", "Salute", "ahola"]
let unexpected = words.sorted()
print(unexpected) // ["Hello", "Salute", "ahola", "bonjour"]
To address this issue, either sort on a lowercase version of the elements:
let words = ["Hello", "bonjour", "Salute", "ahola"]
let sortedWords = words.sorted { $0.lowercased() < $1.lowercased() }
print(sortedWords) // ["ahola", "bonjour", "Hello", "Salute"]
Or import Foundation and use NSString's comparison methods like caseInsensitiveCompare:
let words = ["Hello", "bonjour", "Salute", "ahola"]
let sortedWords = words.sorted { $0.caseInsensitiveCompare($1) == .orderedAscending }
print(sortedWords) // ["ahola", "bonjour", "Hello", "Salute"]
Alternatively, use localizedCaseInsensitiveCompare, which can manage diacritics.
To properly sort Strings by the numeric value they contain, use compare with the .numeric option:
let files = ["File-42.txt", "File-01.txt", "File-5.txt", "File-007.txt", "File-10.txt"]
let sortedFiles = files.sorted() { $0.compare($1, options: .numeric) == .orderedAscending }
print(sortedFiles) // ["File-01.txt", "File-5.txt", "File-007.txt", "File-10.txt", "File-42.txt"]
