How to replace specific word to NSAttributedString in swift

Question

I want to replace all the specific words in a string.

For example)

var str = "apple is red. apple is green"

I want to change background the word "apple" only in the sentence.

So I tried the following.

let resultString = NSMutableAttributedString(string: str)

let apple = NSMutableAttributedString(string: "apple")

apple.addAttribute(NSAttributedStringKey.backgroundColor, value: UIColor.yellow, range: NSRange(location: 0, length: apple.length))

resultString.replaceCharacters(in: (str as NSString).range(of: "apple"), with: apple)

but result that.

resultString = "apple(change background color) is red. apple(did not change background color) is green"

I want result -> "apple(change background color) is red. apple(change background color) is green.

What should I do?

Answer 1

You can do it by regular expression

var str = "apple is red. apple is green"

    let resultString = NSMutableAttributedString(string: str)

    let apple = NSMutableAttributedString(string: "apple")

    apple.addAttribute(NSAttributedStringKey.backgroundColor, value: UIColor.yellow, range: NSRange(location: 0, length: apple.length))

    let components = str.components(separatedBy: " ")

    do {
        let regex = try NSRegularExpression(pattern: "apple", options: NSRegularExpression.Options.caseInsensitive)


        regex.enumerateMatches(in: str, options: [NSRegularExpression.MatchingOptions.reportCompletion], range: NSRange.init(location: 0, length: str.count)) { (result, flags, pointer) in

            resultString.replaceCharacters(in: result?.range(at: 0) ?? NSRange(), with: apple)
        }
    }catch let error {
        print(error)
    }

    print(resultString)