How do I check if a string contains another string in Swift?

Question

In Objective-C the code to check for a substring in an NSString is:

NSString *string = @\"hello Swift\";
NSRange textRange =[strin         


        

Answer 1

Here is my first stab at this in the swift playground. I extend String by providing two new functions (contains and containsIgnoreCase)

extension String {
    func contains(other: String) -> Bool{
        var start = startIndex

        do{
            var subString = self[Range(start: start++, end: endIndex)]
            if subString.hasPrefix(other){
                return true
            }

        }while start != endIndex

        return false
    }

    func containsIgnoreCase(other: String) -> Bool{
        var start = startIndex

        do{
            var subString = self[Range(start: start++, end: endIndex)].lowercaseString
            if subString.hasPrefix(other.lowercaseString){
                return true
            }

        }while start != endIndex

        return false
    }
}

Use it like this

var sentence = "This is a test sentence"
sentence.contains("this")  //returns false
sentence.contains("This")  //returns true
sentence.containsIgnoreCase("this")  //returns true

"This is another test sentence".contains(" test ")    //returns true

I'd welcome any feedback :)