無法從 Swift 中較大的多行字符串中提取 substring

Question

我提取了一些 HTML 代碼並將其存儲在一個名為“html”的字符串中。 我想從這個 HTML 代碼中提取星數。 查看 html，我認為最簡單的方法是在 html 字符串和 go 中查找“星星”一詞。 所以我寫了這段代碼：

var s = "stars"
if (html.contains(s)) {
   print("Found stars")
}

但是，由於某種原因，這不起作用，並且不會在 xcode 的右下部分打印“Found Stars”。 我究竟做錯了什么？

這是存儲在 html 字符串變量中的 html 代碼的一部分

 </h2> <div class="a-row a-size-small a-color-secondary"><span class="a-size-small" dir="auto">by </span><span class="a-size-small" dir="auto">John Bolton</span></div> </div> <div class="a-section a-spacing-none a-spacing-top-mini"> <div class="a-row a-size-small"> <span aria-label="3.1 out of 5 stars"> <i class="a-icon a-icon-star-small a-star-small-3 aok-align-bottom"><span class="a-icon-alt">3.1 out of 5 stars</span></i> </span>

這是我用來提取 HTML 的代碼：

            var html = ""
            let scheme = "https"
            let host = "www.amazon.com"
            let path = "/s"
            let k =  ocrText
            let i = "stripbooks"
            let kItem = URLQueryItem(name: "k", value: k)
            let iItem = URLQueryItem(name: "i", value: i)
            
            var urlComponents = URLComponents()
            urlComponents.scheme = scheme
            urlComponents.host = host
            urlComponents.path = path
            urlComponents.queryItems = [kItem, iItem]
            
            guard let url = urlComponents.url else { return }
            
            print(url)
            
            
            
            //URL(string: "https://www.amazon.com" + "/s?k=" + text   + "&i=stripbooks")!
            URLSession.shared.dataTask(with: url) { data, response, error in
                guard let data = data else {
                    print(error ?? "")
                    return
                }
                html = String(data: data, encoding: .utf8)!

我認為可能是 .contains 方法只檢查了 HTML 的第一行，但我可能錯了。

關於評級的更多代碼：

URLSession.shared.dataTask(with: url) { data, response, error in
                    guard let data = data else {
                        print(error ?? "")
                        return
                    }
                    html = String(data: data, encoding: .utf8)!
                    let pattern = #"(\d.\d) out of 5 stars"#
                    if let range = html.range(of: pattern, options: .regularExpression) {
                        let rating = html[range].prefix(3)
                        ocrText = ocrText + rating
                        print("testing", ocrText)
                    }
                    
                }.resume()
                
                print("LATER:", ocrText)
                
                
                
                
                
                DispatchQueue.main.async {
                    self.ocrTextView.text = ocrText
                    self.scanButton.isEnabled = true
                }

Answer 1

創建html String ，如下所示，

let html = """
</h2>
<div class="a-row a-size-small a-color-secondary"><span class="a-size-small" dir="auto">by </span><span class="a-size-small" dir="auto">John Bolton</span></div>
                    </div>
                    
                        <div class="a-section a-spacing-none a-spacing-top-mini">
                            <div class="a-row a-size-small">


<span aria-label="3.1 out of 5 stars">
    

<i class="a-icon a-icon-star-small a-star-small-3 aok-align-bottom"><span class="a-icon-alt">3.1 out of 5 stars</span></i>

</span>
"""

現在下面的代碼將在您的控制台中打印找到的星星。

var s = "stars"
if (html.contains(s)) {
   print("Found stars")
}

Answer 2

確保您使用 escaping 特殊字符（即，將“替換為 \”）存儲字符串，如下所示：

var str = "</h2> <div class=\"a-row a-size-small a-color-secondary\"><span class=\"a-size-small\" dir=\"auto\">by </span><span class=\"a-size-small\" dir=\"auto\">John Bolton</span></div></div><div class=\"a-section a-spacing-none a-spacing-top-mini\"><div class=\"a-row a-size-small\"><span aria-label=\"3.1 out of 5 stars\"><i class=\"a-icon a-icon-star-small a-star-small-3 aok-align-bottom\"><span class=\"a-icon-alt\">3.1 out of 5 stars</span></i></span>"