如何截断字符串中的字符？

Question

在这里，我只需要截断https的s字母，有人可以帮助我如何从字符串下面截断它吗？

https://192.168.1.11/magento2/pub/media/ewl_bannerslider/slides/5.jpg

Answer 1

What you actually want is to change the scheme from "https" to "http" in an URL string. URLs can be safely manipulated using the URLComponents type:

var urlString = "https://192.168.1.11/magento2/pub/media/ewl_bannerslider/slides/5.jpg"

if var urlComponents = URLComponents(string: urlString), urlComponents.scheme == "https" {
    urlComponents.scheme = "http"
    urlString = urlComponents.string!
}

print(urlString)
// http://192.168.1.11/magento2/pub/media/ewl_bannerslider/slides/5.jpg

If your intention is to create an URL request then you don't need the modified string, but only the URL(Request) with the changed scheme:

let urlString = "https://192.168.1.11/magento2/pub/media/ewl_bannerslider/slides/5.jpg"

guard var urlComponents = URLComponents(string: urlString) else {
    // ... invalid URL string, bail out ...
}
if urlComponents.scheme == "https" {
    urlComponents.scheme = "http"
}
guard let url = urlComponents.url else {
    // ... invalid URL, bail out ...
}

let request = URLRequest(url: url)
// ...

Answer 2

Try below code snippet:

let tmpStr = "https://192.168.1.11/magento2/pub/media/ewl_bannerslider/slides/5.jpg"
      let modifiedStr  = tmpStr.replace("https", withString:"http")
    extension String
    {
        func replace(target: String, withString: String) -> String
        {
            return self.replacingOccurrences(of: target, with: withString, options: NSString.CompareOptions.literal, range: nil)
        }
    }

Answer 3

It's easy to replace text inside a string with the help of the method replacingOccurrences(of:) it is available from swift2 onwards.

let originalStr = "https://192.168.1.11/magento2/pub/media/ewl_bannerslider/slides/5.jpg"
let finalStr = originalStr.replacingOccurrences(of: "https", with: "http")
 print(finalStr)

option2

let str = "https://192.168.1.11/magento2/pub/media/ewl_bannerslider/slides/5.jpg"

    if str.utf16.count >= 5{
        let a = str.index(str.startIndex, offsetBy: 5)
        let result =  String(str[..<a])
        let replaced = str.replacingOccurrences(of: result, with: "http")
        print(replaced)

    }else{
        //lenght in shorter
    }

option3

 var str = "https://192.168.1.11/magento2/pub/https/ewl_bannerslider/slides/5.jpg"
    str = str.stringByReplaceonFirstOccurrenceOfString(target: "https", withString: "http")
    print(str)



extension String
{
func stringByReplaceonFirstOccurrenceOfString(
    target: String, withString replaceString: String) -> String
{
    if let range = self.range(of: target) {
        return self.replacingCharacters(in: range, with: replaceString)
    }
    return self
}
}