Extract Last Word in String with Swift

Question

What is the way of extracting last word in a String in Swift? So if I have \"Lorem ipsum dolor sit amet\", return \"amet\". What is the most efficient way of doing this?

Answer 1

I would also consider using componentsSeparatedByCharactersInSet, and using the whitespace character set:

let string = "Lorem ipsum dolor sit amet"
let stringArray = string.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
print(stringArray.last)

Answer 2

First use componentsSeparatedByString to split your string into an array by space, then get the last word of the array using .last

var string = "Lorem ipsum dolor sit amet"
var stringArr = string.componentsSeparatedByString(" ")

var lastWord = stringArr.last //amet

Answer 3

The other answers are fine if you want to include Foundation classes. If you want to use Swift-only classes then you can do it this way:

One way to do it is to use indices. This is probably the fastest way with long strings:

Swift 4:

let str = "Lorem ipsum dolor sit amet"
let size = str.reversed().firstIndex(of: " ") ?? str.count
let startWord = str.index(str.endIndex, offsetBy: -size)
let last = str[startWord...] // -> "amet"

Or you could split the string:

Swift 4:

let str = "Lorem ipsum dolor sit amet"
let split = str.split(separator: " ")
let last    = String(split.suffix(1).joined(separator: [" "]))
let lastTwo = String(split.suffix(2).joined(separator: [" "]))

print(last)    // -> "amet"
print(lastTwo) // -> "sit amet”

Swift 3:

let str = "Lorem ipsum dolor sit amet"
let split = str.characters.split(separator: " ")
let last    = String(split.suffix(1).joined(separator: [" "]))
let lastTwo = String(split.suffix(2).joined(separator: [" "]))

print(last)    // -> "amet"
print(lastTwo) // -> "sit amet”

Swift 2:

let str = "Lorem ipsum dolor sit amet"
let split = str.characters.split(Character(" "))
let last    = String(split.suffix(1).joinWithSeparator([" "]))
let lastTwo = String(split.suffix(2).joinWithSeparator([" "]))

print(last)    // -> "amet"
print(lastTwo) // -> "sit amet"

Answer 4

You can use String method enumerateSubstringsInRange. First parameter just pass your string Range<Index>, and the option .byWords. Just append each substring to the resulting collection and return it.

Swift 5 or later (for older Swift syntax check edit history)

import Foundation

extension StringProtocol { // for Swift 4 you need to add the constrain `where Index == String.Index` 
    var byWords: [SubSequence] {
        var byWords: [SubSequence] = []
        enumerateSubstrings(in: startIndex..., options: .byWords) { _, range, _, _ in
            byWords.append(self[range])
        }
        return byWords
    }
}

---

Usage:

let sentence = "Out of this world!!!"
let words = sentence.byWords             // ["Out", "of", "this", "world"]
let firstWord = words.first      // "Out"
let lastWord = words.last         // world"
let first2Words = words.prefix(2) // ["Out", "of"]
let last2Words = words.suffix(2)   // ["this", "world"]

---

Without import Foundation

Cleaning punctuation characters filtering the letters and spaces of the string

let clean = sentence.filter{ $0.isLetter || $0.isWhitespace }

find the index after the index of the last space in a string

if let lastIndex = clean.lastIndex(of: " "), let index = clean.index(lastIndex, offsetBy: 1, limitedBy: clean.index(before: clean.endIndex)) {
    let lastWord = clean[index...]
    print(lastWord)   // "world"
}

find the index of the first space in a string

if let index = clean.firstIndex(of: " ") {
    let firstWord = clean[...index]
    print(firstWord)  // "Out""
}

Answer 5

Swift 5

extension String {

    func trim(_ emptyToNil: Bool = true)->String? {
        let text = self.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)
        return emptyToNil && text.isEmpty ? nil : text
    }

    var lastWord: String? {
        if let size = self.lastIndex(of: " "), size >= self.startIndex {
            return String(self[size...]).trim()
        }
        return nil
    }

}

Usage

print("Out of this world!!!".lastWord ?? "") // world!!!

Answer 6

The same solution by '@Leo Dabus' but without slices: (Swift 4.x)

    let fullName = "Williams Diaz Robert"
    let words = fullName.components(separatedBy: " ")
    if(words.count < 2) {
        return
    }
    let fistName = String(words.last ?? "") //Robert
    let lastNameArray = words.prefix(words.count - 1)   //["Williams","Diaz"]: [String]
    let lastName = lastNameArray.joined(separator: " ") // "Williams Diaz"