在java中反转句子

Question

我正在挑战在https://www.codewars.com/kata/reversed-words/train/java 反转给定句子，我已经设法将句子反转为预期但在他们的 JUnit 测试中遇到了一个小错误。 这是我将任何句子反转为预期结果的代码，例如

“最大的胜利是不需要战斗的胜利”
// 应该返回 "battle no requires which is the 胜利最大"

我的代码

    public class ReverseWords{
 public static String reverseWords(String sentence){
   String reversedsentence ="";

       for(int x=sentence.length()-1;x>=0;--x){  //Reversing the whole sentence                                                           

            reversedsentence += sentence.charAt(x);                       
       } //now you are assured the whole sentence is reversed

       String[]words = reversedsentence.split(" "); //getting each word in the  reversed sentence and storing it in a string array

       String ExpectedSentence= "";
        for(int y=0;y<words.length;y++){
            String word =words[y];   //getting word by word in the  string array

            String reverseWord = "";
            for(int j=word.length()-1;j>=0;j--){    /*Reversing each word  */

                 reverseWord += word.charAt(j);    
            }
            ExpectedSentence +=reverseWord + " ";   //adding up the words to get the expected sentence

        }

            return ExpectedSentence;
    }
}

还有JUnit测试代码

import org.junit.Test;
import static org.junit.Assert.assertEquals;
import org.junit.runners.JUnit4;

// TODO: Replace examples and use TDD development by writing your own tests

public class SolutionTest {
    @Test
    public void testSomething() {
         assertEquals(ReverseWords.reverseWords("I like eating"), "eating like I");
         assertEquals(ReverseWords.reverseWords("I like flying"), "flying like I");
         assertEquals(ReverseWords.reverseWords("The world is nice"), "nice is world The");
    }
}

错误出现了

> expected:<eating like I[ ]> but was:<eating like I[]> 

有关错误的更多详细信息是

> org.junit.ComparisonFailure:  expected:<eating like I[ ]> but was:<eating like I[]>   at org.junit.Assert.assertEquals(Assert.java:115)   at org.junit.Assert.assertEquals(Assert.java:144)   at SolutionTest.testSomething(SolutionTest.java:10)

您只需点击此链接并粘贴我的代码，您将看到一个代码游乐场Train: Reversed Words |CodeWars

Answer 1

试试这个方法

public static void main(String[] args) {
    Assert.assertEquals("sentence a is This", reverseSentence("This is a sentence"));
}


public static String reverseSentence(String sentence) {
    String[] words = sentence.split(" ");
    for (int i = 0; i < words.length / 2; i++) {
        String temp = words[i];
        words[i] = words[words.length - i - 1];
        words[words.length - i - 1] = temp;
    }
    return String.join(" ", words);
}

使用String.join()，您可以省去麻烦，避免将分隔符添加到最后一个元素。

Answer 2

首先您错误地使用了Assert.assertEquals()，因为应该首先提供expected 参数。将其更改为：

assertEquals("eating like I", ReverseWords.reverseWords("I like eating"));

这使错误更清楚：

> expected:<eating like I[]> but was:<eating like I[ ]> 

这是由于以下行在处理每个reverseWord 后盲目添加空格：

ExpectedSentence +=reverseWord + " ";   //adding up the words to get the expected sentence