How to compare two strings ignoring case in Swift language?

Question

How can we compare two strings in swift ignoring case ? for eg :

var a = \"Cash\"
var b = \"cash\"

Is there any method that will return tru

Answer 1

localizedCaseInsensitiveContains : Returns whether the receiver contains a given string by performing a case-insensitive, locale-aware search

if a.localizedCaseInsensitiveContains(b) {
    //returns true if a contains b (case insensitive)
}

Edited:

caseInsensitiveCompare : Returns the result of invoking compare(_:options:) with NSCaseInsensitiveSearch as the only option.

if a.caseInsensitiveCompare(b) == .orderedSame {
    //returns true if a equals b (case insensitive)
}

Answer 2

You can just write your String Extension for comparison in just a few line of code

extension String {

    func compare(_ with : String)->Bool{
        return self.caseInsensitiveCompare(with) == .orderedSame
    } 
}

Answer 3

Swift 3: You can define your own operator, e.g. ~=.

infix operator ~=

func ~=(lhs: String, rhs: String) -> Bool {
   return lhs.caseInsensitiveCompare(rhs) == .orderedSame
}

Which you then can try in a playground

let low = "hej"
let up = "Hej"

func test() {
    if low ~= up {
        print("same")
    } else {
        print("not same")
    }
}

test() // prints 'same'

Answer 4

Swift 4, I went the String extension route using caseInsensitiveCompare() as a template (but allowing the operand to be an optional). Here's the playground I used to put it together (new to Swift so feedback more than welcome).

import UIKit

extension String {
    func caseInsensitiveEquals<T>(_ otherString: T?) -> Bool where T : StringProtocol {
        guard let otherString = otherString else {
            return false
        }
        return self.caseInsensitiveCompare(otherString) == ComparisonResult.orderedSame
    }
}

"string 1".caseInsensitiveEquals("string 2") // false

"thingy".caseInsensitiveEquals("thingy") // true

let nilString1: String? = nil
"woohoo".caseInsensitiveEquals(nilString1) // false