Question

我正在研究一个需要返回某个子字符串3次的简单程序。例如，诸如makeThreeSubstr（＆＃34; hello＆＃34;，0,2）之类的调用应返回＆＃34; hehehe＆＃34;。我已准备好返回代码＆＃34;他＆＃34;，但我不知道连续三次输出子字符串的简单方法。非常感谢任何帮助。

class Main {
 public static String makeThreeSubstr (String word, int startIndex, int endIndex)
 {
  return (word.substring(startIndex, endIndex));

 }

 public static void main(String[] args){
    System.out.println(makeThreeSubstr("hello",0,2)); //should be hehehe
    System.out.println(makeThreeSubstr("shenanigans",3,7)); //should be naninaninani
  }
}

Answer 1

String s = word.substring(startIndex, endIndex);
return s + s + s;

Answer 2

根据这个答案Simple way to repeat a String in java

String  repeated = new String(new char[3]).replace("\0", word.substring(startIndex, endIndex));
return repeated;

Answer 3

快速而肮脏的方法是：

public static String makeThreeSubstr (String word, int startIndex, int endIndex)
{
  String substring = word.substring(startIndex, endIndex);
  return substring + substring + substring;
}

Java子串迭代问题

3 个答案: