如何反转字符串中的单词但将标点符号保持在正确的位置？

Question

我编写了以下代码来反转输入字符串：

  Scanner s = new Scanner(System.in);
  System.out.println("Please enter a sentence:");
  String sentence = s.nextLine();

  String[] words = sentence.split(" ");
  String reversedSentence = "";

  for(int i = words.length - 1; i >= 0 ; i--)
  {
      reversedSentence += words[i] + " ";
  }

  System.out.println(reversedSentence);

但是它没有给我想要的结果。我需要标点符号成为它所附单词的一部分，但仍要切换到单词的右侧。例如，如果您输入

“The quick brown fox jumps over the lazy dog”

我希望输出为

“dog lazy the over jumps fox brown quick The”

我实际得到的是：

dog” lazy the over jumps fox brown quick “The

Answer 1

如果只想处理输入首尾的双引号，只需将子串反转，稍后再添加即可。例如

if (sentence.startsWith("\"") && sentence.endsWith("\"")) {
    sentence = sentence.substring(1, sentence.length()-1);
}

最后在拆分、反转和连接打印之后：

System.out.println('"' + reversedSentence + '"');

还有 2 条建议：

1) 您的 for 循环留下尾随 space。最后一个字不要加space
2) 你应该使用 StringBuilder 来连接字符串。例如

StringBuilder reversedSentence = new StringBuilder();

for (int i = words.length - 1; i > 0; i--) {
    reversedSentence.append(words[i]).append(' ');
}
reversedSentence.append(words[0]);
System.out.println('"' + reversedSentence.toString() + '"');

Answer 2

将字符串分解为数组并使用Collections.reverse()如下：

public class StringReverse {

 public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        System.out.println("Please enter a sentence:");
        String sentence = s.nextLine();
        String[] array = sentence.replaceAll("\“|”", "").split(" ");
        StringBuilder sb = new StringBuilder();
        List<String> list = Arrays.asList(array);
        Collections.reverse(list);
        array = (String[]) list.toArray();
        for (int i = 0; i < array.length; i++) {
            sb.append(array[i]).append(" ");
        }
        System.out.println(sentence.charAt(0)
                + sb.toString().replaceAll(" $", "")
                + sentence.charAt(sentence.length() - 1));
        s.close();
    }
}

用Java8Arrays.stream，就这么简单：

import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.Scanner;
import java.util.stream.Collectors;

public class StringReverse {

    Scanner s = new Scanner(System.in);
    System.out.println("Please enter a sentence:");
    String sentence = s.nextLine();
    StringBuilder sb = new StringBuilder();
    Arrays.stream(sentence.replaceAll("\“|”", "").split(" "))
            .collect(Collectors.toCollection(ArrayDeque::new))
            .descendingIterator()
            .forEachRemaining(e -> sb.append(e).append(" "));
    System.out.println(sentence.charAt(0)
            + sb.toString().replaceAll(" $", "")
            + sentence.charAt(sentence.length() - 1));
    s.close();
}

Answer 3

如果标点符号也打开和关闭。就像你的例子一样。你可以使用这样的东西：

很脏。我稍后会编辑它。我做的不多java。

    String[][] punctuations = new String[][] {
            {"(", ")"},
            {"“", "”"}
    };

    for (String[] punctuation : punctuations) {
        if (sentence.contains(punctuation[0])) {
            int index_0 = sentence.indexOf(punctuation[0]);
            int index_of_next_space = sentence.indexOf(" ", index_0);
            String old_string_0 = sentence.substring(index_0, index_of_next_space);
            String new_string_0 = old_string_0.replace(punctuation[0], "") + punctuation[1];

            int index_1 = sentence.indexOf(punctuation[1]);
            int index_of_last_space = sentence.lastIndexOf(" ", index_1);
            String old_string_1 = sentence.substring(index_of_last_space+1, index_1 + 1);
            String replaced_string_1 = punctuation[0] + old_string_1.replace(punctuation[1], "");
            sentence = sentence.replace(old_string_0, new_string_0);
            sentence = sentence.replace(old_string_1, replaced_string_1);
        }
    }

现在反转你的字符串。

输入：

“The (quick brown's) fox jumps over the lazy dog”

输出：

“dog lazy the over jumps fox (brown's quick) The”

这可以改进。就像我之前说的，我做的不多 java :/.

如何反转字符串中的单词但将标点符号保持在正确的位置？

How to reverse words in a string but keep punctuation in the right place?

java

string

reverse