Separate array of strings by string separator into array of strings

Question

I currently have an array being created like this

let stringSeparator1 = "some string"

if let contentArray = dataString?.components(separatedBy: stringSeparator1) {

    if contentArray.count > 1 {

        //Separate contentArray into array of relevant results
        let stringSeparator2 = "</p>"

        let result = contentArray[1].components(separatedBy: stringSeparator2)

This works great for 1 index position of contentArray. But what I really want to do is go through contentArray from index 1 to contentArray.count and delimit all of the data by stringSeparator2. I've tried several methods using loops and can't find a way that gives me what I need.

Consider to use NSScanner or – preferable – regular expression to parse HTML. — vadian
– vadian, Commented May 16, 2017 at 6:37

Maxim Kosov · Accepted Answer · 2017-05-16 14:21:44Z

1

Use .map to get array of arrays and .flatMap to get array of strings. You can use various filtering methods (e.g. .filter, .dropFirst, .dropLast, .dropWhile, etc)

let dataString: String? = "0-1-2,3-4-5,6-7-8"

// map will result in array of arrays of strings. dropFirst will skip first part (see dropLast, etc)
let mapResult = dataString?.components(separatedBy: ",").dropFirst().map { $0.components(separatedBy: "-") }
print(mapResult) // Optional([["3", "4", "5"], ["6", "7", "8"]])

// flatMap will result in array of strings. dropFirst will skip first part (see dropLast, etc)
let flatMapResult = dataString?.components(separatedBy: ",").dropFirst().flatMap { $0.components(separatedBy: "-") }
print(flatMapResult) // Optional(["3", "4", "5", "6", "7", "8"])

edited May 16, 2017 at 14:21

answered May 16, 2017 at 6:24

Maxim Kosov

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4 Comments

froggomad Over a year ago

You didn't know this because it's not in my code example, but dataString is an optional string. That said, flatMap provides the closest result to what I'm looking for. Thanks very much

Maxim Kosov Over a year ago

This doesn't matter. Just add ? after dataString. Modified example to reflect that.

froggomad Over a year ago

Xcode says it matters because Type String doesn't contain member .components or .dropFirst or .flatMap. Feel free to edit your answer to reflect this, or what I've done is applied this to contentArray as per my question

froggomad Over a year ago

Thanks much. I somehow missed the .map step when checking your answer the first time. That said, since I already had contentArray created and separated by a string, I did this: let flatMapResult = contentArray.dropFirst().flatMap {$0.components(separatedBy: ",")}

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