如何检测字符串中的字母并切换它们？

Question

如何检测字符串中的字母并切换它们？

我想过这样的事......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，如果你有兴趣在一个面露正则表达式：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

你可以使用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，你也必须执行一些错误处理时，有没有斜线等..

Answer 4

可以使用string.split（分离器，限）

限制：可选。指定拆分的数量的整数，拆分限制后的项目将不会被包含在阵列

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

你也可以使用的StringTokenizer拆分的字符串中。

String main =“hello/bye”; StringTokenizer st = new StringTokenizer（main，“\”）;

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

String newMain = part2 +“\”+ part1;