如何检测字符串中的字母并切换它们？

Question

如何检测String中的字母并进行切换？

我想过类似的事情...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

使用String.substring:

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

Answer 2

好吧，如果您对 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("(.*?)/(.*)", "/")); // () is a capturing group. it captures everything inside the braces.  and  are the captured values. You capture values and then swap them. :P
        //}

    }

O/P :

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

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];

当然你还必须在没有斜杠等的情况下实现一些错误处理。

Answer 4

你可以使用string.split(分隔符,限制)

限制：可选。一个整数，指定拆分次数，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 来拆分字符串。

字符串主="hello/bye"； StringTokenizer st = new StringTokenizer(main,"\");

字符串第 1 部分 = st.nextToken(); 字符串第 2 部分 = st.nextToken();

String newMain = part2 + "\" + part1;

如何检测字符串中的字母并切换它们？

How to detect the letters in a String and switch them?

java

string