iOS通过URL获取HTML中标题

获取标题

String扩展一个方法
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private let patternTitle = "(?<=title>).*(?=</title)"
extension String {
    static func parseHTMLTitle(_ urlString: String) -> String? {
        let url = URL(string: urlString)!
        do {
            let html = try String(contentsOf: url, encoding: .utf8)
            let range = html.range(of: patternTitle, options: String.CompareOptions.regularExpression, range: html.startIndex..<html.endIndex, locale: nil)
            guard let tempRange = range else { return "" }
            let titleStr = html[tempRange]
            return String(titleStr)
        } catch {
            return ""
        }
    }
}
iOS 中简单正则表达式

iOS 中 正则表达式中的\ 需要使用 \\ 来表示

// 获取
let testStr = "我到底是[iOS]开发还是[产品]经理"

// 获取 "[" 和 "]" 之间的所有内容, 左边[ 起一直到 右边 ] 结束的所有内容 
let pattern1 = "\\[.*\\]" // [iOS]开发还是[产品]

// 获取 "[" 和 "]" 之间的所有内容，包括[]
let pattern2 = "\\[.*?\\]"    // [iOS]

// 获取第一个 "[" 和 "]" 之间的所有内容 不包括[] 
let pattern3 = "(?<=\\[).*?(?=\\])" // iOS

// 获取html中 title 标签中内容
let pattern5 = "(?<=title>).*(?=</title)"
获取范围截取子串
let testRange1 = testStr.range(of: pattern1, options: String.CompareOptions.regularExpression, range: testStr.startIndex..<testStr.endIndex, locale: nil)
    let result1 = String(testStr[testRange1!])


let testRange2 = testStr.range(of: pattern2, options: String.CompareOptions.regularExpression, range: testStr.startIndex..<testStr.endIndex, locale: nil)
let result2 = String(testStr[testRange2!])


let testRange3 = testStr.range(of: pattern3, options: String.CompareOptions.regularExpression, range: testStr.startIndex..<testStr.endIndex, locale: nil)
let result3 = String(testStr[testRange3!])

print(result1) 
print(result2) 
print(result3)
正则表达式

通过URL解析html中的标题

  • 获取html字符串
  • 正则匹配
  • 生成字符串Range
  • 截取字符串

匹配一次直接返回结果

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// 生成表达式
let regular = try NSRegularExpression(pattern: pattern5, options: .caseInsensitive) 
 

// 开始匹配  
let matchResult1 = regular.firstMatch(in: html, options: NSRegularExpression.MatchingOptions.reportProgress, range: NSMakeRange(0, html.count))

// 获取匹配结果范围
let matchRange = matchResult1?.range
let range = Range(matchRange!)!
    
// 生成String.Index 类型范围 
let startIndex = html.index(html.startIndex, offsetBy: range.lowerBound)
let endIndex = html.index(html.startIndex, offsetBy: range.upperBound)
let range3 = Range(uncheckedBounds: (lower: startIndex, upper: endIndex))

// 截取字符串
let result1 = String(html[range3])
print(result1)

全部匹配后返回结果时一个集合

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let matchResult2 = regular.matches(in: html, options: .reportProgress, range: NSMakeRange(0, html.count))
            matchResult2.forEach { (result) in
let range = Range(result.range)!
    
let startIndex = html.index(html.startIndex, offsetBy: range.lowerBound)
let endIndex = html.index(html.startIndex, offsetBy: range.upperBound)
    
let subStr2 = html[Range(uncheckedBounds: (startIndex, endIndex))]
print(String(subStr2))
}

将匹配到的内容提还

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let str3 = regular.stringByReplacingMatches(in: html, options: .reportProgress, range: NSMakeRange(0, html.count), withTemplate: "====")