Get specific values from a string and create array - ios

Question

From some URL I create an array of strings, and I would like to grab some data from those strings and turn them into another array of variables.
My array of strings looks like this:
#EXTINF:-1 tvg-logo="https://www.thetvdb.com/banners/posters/248741-9.jpg" group-title="Broke Girls", trailer
#EXTINF:-1 tvg-logo="https://www.thetvdb.com/banners/posters/210841-10.jpg" group-title="Alphas", Alphas trailer
#EXTINF:-1 tvg-logo="https://www.thetvdb.com/banners/posters/309053-2.jpg" group-title="American Gothic", trailer
Every line represents a new string item from my array.
I am trying to create a function to do it, but until now, I only have this:
func grabValuesFromUrl(savedUrl: String) {
var trailersArray = []()
if let url = URL(string: savedUrl) {
do {
let contents = try String(contentsOf: url)
contents.enumerateLines { (line, stop) in
// here i need to grab the values from every string inside tvg-logo="", group-title="", and the last one after "," that's the title, and put them into trailersArray[], afterwards i will make some model class to get the data like trailersArray.logo and trailersArray.group and trailersArray.title
}
} else {
print("no url added")
}
}
Thanks in advance

Answer 1

I'd use regex for anything related to extracting data from a string with known format. For this, lets first define helper function:
func matches(for regex: String, inText text: String) -> [String] {
guard let regex = try? NSRegularExpression(pattern: regex, options: [.caseInsensitive]) else { return [] }
let nsString = text as NSString
let results = regex.matches(in: text, options: [], range: NSMakeRange(0, nsString.length))
return results.flatMap { result in
(0..<result.numberOfRanges).map {
result.range(at: $0).location != NSNotFound ? nsString.substring(with: result.range(at: $0)) : ""
}
}
}
And then define the regular expression that will extract required data:
let regex = "^.*tvg-logo=\"(.+)\".*group-title=\"(.+)\".*, (.+)$"
Beware that this regex is sensitive to data format so you'll have to adapt it to new one in case of changes.
Finally, in your line enumeration closure you can extract the data:
let parts = matches(for: regex, inText: line).dropFirst()
parts is now an array with three corresponding items (we drop the first one because it is the line itself) if the line matches the regex, so we can, for example, append a tuple with values to the array:
if parts.count == 3 {
trailersArray.append((logo: parts[0], group: parts[1], title: parts[2]))
}