Split HTML String between strings Swift

Question

Is it possible to take just a part of the HTML string that I have obtained passing the URL?

Example code below:

  let myURLString = "https://myUrl.something"
        guard let myURL = NSURL(string: myURLString) else {
            print("Error: \(myURLString) doesn't seem to be a valid URL")
            return
        }
        do {
            let myHTMLString = try String(contentsOf: myURL as URL)
            let htmlString = String(myHTMLString)
            print("HTML: \(myHTMLString)")
        } catch let error as NSError {
            print("Error: \(error)")
        }

I want to take what's inside the tag <h3 class="post-title"> to </h3>.

I know that I should use the regular expressions but I don't really know how to set it in the right way. I tried something like this:

  let myURLString = "https://www.fvgtech.it/category/podcast/"
        guard let myURL = NSURL(string: myURLString) else {
            print("Error: \(myURLString) doesn't seem to be a valid URL")
            return
        }
        do {
            let myHTMLString = try String(contentsOf: myURL as URL)
            let htmlString = String(myHTMLString)

            if let match = htmlString.range(of: "(<h3.+)", options: .regularExpression) {
                print("Found",htmlString.substring(with: match))
            }


            print("HTML: \(myHTMLString)")
        } catch let error as NSError {
            print("Error: \(error)")
        }

But it's printing just <h3 class="post-title"> and not what's in the middle. Thanks in advance!

@a.masri thanks for the reply! Actually if I'll put what you texted it's taking the first bracket, but if I'll modify <h3[^>].*> it will show to me again just <h3 class="post-title"> and not what's between the <h3 and the \h3> — Pietro Messineo
– Pietro Messineo, Commented May 6, 2018 at 19:29
look this regex regex101.com/r/CV67Yl/1 and check result in group 1 this is what you wan — a.masri
– a.masri, Commented May 6, 2018 at 19:38
I checked it but Xcode it's returning me "Invalid escape sequence in literal" — Pietro Messineo
– Pietro Messineo, Commented May 6, 2018 at 19:43
Ok, try this String(htmlString.filter { !" \n\t\r".contains($0) }).range(of: "<h3.*?>(.+)((.*)+(.+))+</h3>", options: .regularExpression) But I do not advise you to use this method because it will take a very long time to better use this library github.com/scinfu/SwiftSoup — a.masri
– a.masri, Commented May 6, 2018 at 20:30

Abdelahad Darwish · Accepted Answer · 2019-01-18 15:03:27Z

3

Just we need to search all substrings between start String and end String See Extension of String

 let myURLString = "https://www.fvgtech.it/category/podcast/"
    guard let myURL = NSURL(string: myURLString) else {
        print("Error: \(myURLString) doesn't seem to be a valid URL")
        return
    }
    do {
        let myHTMLString = try String(contentsOf: myURL as URL)
        let htmlString = String(myHTMLString)
        print(htmlString.allStringsBetween("<h3 class=\"post-title\">", andString: "</h3>"))

    } catch let error as NSError {
        print("Error: \(error)")
    }

Extension for String

extension String{

  func allStringsBetween(start: String, end: String) -> [Any] {
            var strings = [Any]()
            var startRange: NSRange = (self as NSString).range(of: start)

            while true {
                if startRange.location != NSNotFound {
                    var targetRange = NSRange()
                    targetRange.location = startRange.location + startRange.length
                    targetRange.length = self.count - targetRange.location
                    let endRange: NSRange = (self as NSString).range(of: end, options: [], range: targetRange)
                    if endRange.location != NSNotFound {
                        targetRange.length = endRange.location - targetRange.location
                        strings.append((self as NSString).substring(with: targetRange))
                        var restOfString =  NSRange()
                        restOfString.location = endRange.location + endRange.length
                        restOfString.length = self.count - restOfString.location
                        startRange = (self as NSString).range(of: start, options: [], range: restOfString)
                    }
                    else {
                        break
                    }
                }
                else {
                    break
                }

            }
            return strings
        }

    }

edited Jan 18, 2019 at 15:03

answered May 6, 2018 at 19:29

Abdelahad Darwish

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5 Comments

Pietro Messineo Over a year ago

But with this I'm just grabbing what's inside <h3 > with result as " class="post-title" " Actually I have something like this <h3 class="post-title"> <a href="fvgtech.it/…" rel="bookmark"> 18 – Fake News Festival e cosa sono le bufale. Ospite Gabriele Franco </a> </h3> and I want to grab it what's between the two <h3> ... </h3>

Abdelahad Darwish Over a year ago

Do you want to grab all what between h3 tags

Pietro Messineo Over a year ago

Yes, so this: <a href="fvgtech.it/…; rel="bookmark"> 18 – Fake News Festival e cosa sono le bufale. Ospite Gabriele Franco </a>

Abdelahad Darwish Over a year ago

@PietroMessineo code update check it and tell me results

Pietro Messineo Over a year ago

That's great ! Thank you so much!

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