我正试图找出另一种方法来做这样的事情,使用范围运算符. 
  
  
 
guard let statusCode = (response as? HTTPURLResponse)?.statusCode,statusCode >= 200 && statusCode <= 299 else {return} 
 也许是这样的:
guard let statusCode = (response as? HTTPURLResponse)?.statusCode where (200...299).contains(statusCode) else {return} 
 要么
guard let statusCode = (response as? HTTPURLResponse)?.statusCode,statusCode case 200...299 else {return} 
 这在Swift中可能吗?
 随你心意: 
  
  
 
                    
                    
                guard
    let statusCode = (response as? HTTPURLResponse)?.statusCode,(200...299).contains(statusCode) else {return} 
 要么:
guard
    let statusCode = (response as? HTTPURLResponse)?.statusCode,case 200...299 = statusCode else {return} 
 要么:
guard
    let statusCode = (response as? HTTPURLResponse)?.statusCode,200...299 ~= statusCode else {return}