Question

How to reverse the first N characters of a string in Java

Answer 1

public class MyClass {
    public static String reverse_first_n_chars(String s, int pos) {
        String tmp = s. substring(0, pos);
        int len = s.length();
         
        s = new StringBuilder(tmp).reverse().toString() + s.substring(pos, len);
 
        return s;        
    }
    public static void main(String args[]) {
        String s = "python programming";
        int pos = 3;
         
        System.out.println(reverse_first_n_chars(s, pos));
    }
}
 
 
/*
run:
 
typhon programming
 
*/

 

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