iOS speech to text conversion in number format

Question

Currently I'm using default iOS speech to text conversion without adding any code for it. When the user says 'five', it is displayed as 'five' or '5'. But, I need it to be converted as '5' always. Is there anything I can do with SFSpeechRecognizer or any other way to achieve this?

Answer 1

This can get you started, but it is not able to handle mixed strings that contain a number AND a non-number. Ideally, you would need to process each word as it comes through, but then that has potential effects for combined numbers (thirty four) for example.

let fiveString = "five"
let numberFormatter = NumberFormatter()
numberFormatter.numberStyle = .spellOut

print(numberFormatter.number(from: fiveString)?.stringValue) // 5

let combinedString = "five dogs"
print(numberFormatter.number(from: combinedString)?.stringValue) // nil

let cString = "five hundred"
print(numberFormatter.number(from: cString)?.stringValue) // 500

let dString = "five hundred and thirty-seven"
print(numberFormatter.number(from: dString)?.stringValue) // 537

Answer 2

You could try to build a simple string extention like so:

extension String {

    var byWords: [String] {
        var byWords:[String] = []
        enumerateSubstrings(in: startIndex..<endIndex, options: .byWords) {
            guard let word = $0 else { return }
            byWords.append(word)
        }
        return byWords
    }

    func wordsToNumbers() -> String {
        let numberFormatter = NumberFormatter()
        numberFormatter.numberStyle = .spellOut

        let formattedString = self.byWords.map {
            return numberFormatter.number(from: $0)?.stringValue ?? $0
        }

        return formattedString.joined(separator: " ")
    }
}

This is a untested (not run / performance not checked) example