Question

如何检测字符串中的字母并切换它们？

我想到了这样的事情......但这可能吗？

//For example:
String main = hello/bye;

if(main.contains("/")){
    //Then switch the letters before "/" with the letters after "/"
}else{
    //nothing
}

Answer 1

好吧，如果你对厚脸皮正则表达式感兴趣：P

public static void main(String[] args) {
        String s = "hello/bye"; 
        //if(s.contains("/")){ No need to check this
            System.out.println(s.replaceAll("(.*?)/(.*)", "$2/$1")); // () is a capturing group. it captures everything inside the braces. $1 and $2 are the captured values. You capture values and then swap them. :P
        //}

    }

O / P：

bye/hello --> This is what you want right?

Answer 2

使用String.substring：

main = main.substring(main.indexOf("/") + 1)
       + "/"
       + main.substring(0, main.indexOf("/")) ;

Answer 3

您可以使用String.split，例如

String main = "hello/bye";
String[] splitUp = main.split("/"); // Now you have two strings in the array.

String newString = splitUp[1] + "/" + splitUp[0];

当然，如果没有斜杠等，你还必须实现一些错误处理。

Answer 4

你可以使用string.split（分隔符，限制）

限制：可选。一个整数，指定拆分数，拆分限制后的项目将不包含在数组

中

String main ="hello/bye";
if(main.contains("/")){
    //Then switch the letters before "/" with the letters after "/"
    String[] parts  = main.split("/",1);

    main = parts[1] +"/" + parts[0] ; //main become 'bye/hello'
}else{
    //nothing
}

Answer 5

您也可以使用StringTokenizer来分割字符串。

String main =＆＃34; hello / bye＆＃34 ;; StringTokenizer st = new StringTokenizer（main，＆＃34; \＆＃34;）;

String part1 = st.nextToken（）; String part2 = st.nextToken（）;

String newMain = part2 +＆＃34; \＆＃34; + part1;

如何检测字符串中的字母并切换它们？

5 个答案: