更改字符串中随机索引的元音:bound必须为正数

Question

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Random;

 public class MachinePedagogy {

     public static void main(String[] args) throws IOException {
         changeVowel("dictionary.txt");
}
private static void changeVowel(String path) throws IOException {
    char ch;
    BufferedWriter bWriter = new BufferedWriter(new FileWriter(new File("changevowel.txt")));
    String aeiou = "aeiou";
    char[] vowels = aeiou.toCharArray();
    BufferedReader bReader = new BufferedReader(new FileReader(new File(path)));
    for(String temp = bReader.readLine(); temp != null; temp = bReader.readLine()){
        int counter = 0;
        char[] characters = temp.toCharArray();
            for(int i = 0; i < temp.length(); i++){
                ch = temp.charAt(i);

                if(
                ch == 'a' || 
                ch == 'e' || 
                ch == 'i' || 
                ch == 'o' || 
                ch == 'u'){
                    counter++;
                    }
                }
            Random rand = new Random();
            int vIndex[] = new int[counter];
            int index = 0;  
            for (int j = 0; j <temp.length(); j++){
                ch = temp.charAt(j);
                if(
                        ch == 'a' || 
                        ch == 'e' || 
                        ch == 'i' || 
                        ch == 'o' || 
                        ch == 'u'){
                    vIndex[index] = j;
                    index++;
                }
            }
            int random2 = (rand.nextInt(vIndex.length));
            int random1 = (rand.nextInt(vowels.length));
            characters[vIndex[random2]] = vowels[random1];
            temp = String.valueOf(characters);
        bWriter.write(temp + "n");
    }
    bReader.close();
    bWriter.close();
     }
 }

为什么在这些数组上我的界有时是负的？

Exception in thread "main" java.lang.IllegalArgumentException: bound must be positive
at java.util.Random.nextInt(Unknown Source)
at MachinePedagogy.changeVowel(MachinePedagogy.java:56)
at MachinePedagogy.main(MachinePedagogy.java:14)

第56行：

characters[vIndex[random2]] = vowels[random1];

第14行：

changeVowel("dictionary.txt");

我想编辑字符串中的随机元音，并将其更改为另一个随机元音，最好与以前不同。Dictionary.txt只是一本斯坦福字典，如果你需要它来编译代码的话。

我发现的许多替换元音的例子都遵循这个逻辑。

temp.replaceAll( "[aeiou]", "?" );

我不想替换所有的元音，只想替换一个随机索引的元音。我认为这可能与nextInt((有关，但当我阅读文档Random#nextInt时，我很困惑为什么会这样。我从其他StackOverflow问题中了解到，这是为数组生成随机索引的有效方法。

我写了一个拼写检查器，想用一个常见的更改单词单个元音的错误来测试它的准确性。我计划稍后通过对dictionary.txt运行changevowel.txt来从我创建的大列表中删除正确的单词&从changevowel.txt中删除正确的单词，但这对眼前的问题并不重要

Answer 1

线程"main"java.lang.IollegalArgumentException中的异常：绑定必须为正位于java.util.Nrandom.nextInt(未知源(

不是来自此行characters[vIndex[random2]] = vowels[random1];

但这条线：

int random2 = (rand.nextInt(vIndex.length));

rand.nextInt的参数必须是> 0，但不知何故是vIndex.length == 0。

Answer 2

试试这个逻辑：

• 从单词中取出元音的所有索引
• 随机选择一个元音索引并将其从单词中删除
• 从"元音列表"中选择另一个与上一步不同的随机元音
• 用新的随机元音替换所选的随机元音

示例：

static String vowels = "AEIOU";
public static void main(String[] args) throws Exception {
    String word = "MIRACULOUSNESS";
    char[] wordArray = word.toCharArray();
    Random rand = new Random();
    List<Integer> vowelIndexes = getVowelIndexes(word);
    // Choose random vowel index and get the random vowel from the word
    int randomVowelIndex = vowelIndexes.get(rand.nextInt(vowelIndexes.size()));
    char randomVowel = word.charAt(randomVowelIndex);
    // Choose random vowel replacement that isn't the same as the randomVowel
    char replacementVowel = randomVowel;
    while (replacementVowel == randomVowel) {
        replacementVowel = vowels.charAt(rand.nextInt(vowels.length()));
    }
    System.out.printf("Before: %sn", word);
    // Replace the vowel
    wordArray[randomVowelIndex] = replacementVowel;
    word = new String(wordArray);
    System.out.printf("After : %sn", word);
}
public static List<Integer> getVowelIndexes(String word) {
    List<Integer> result = new ArrayList();
    for (int i = 0; i < word.length(); i++) {
        if (vowels.contains(""+word.charAt(i))) {
            result.add(i);
        }
    }
    return result;
}

结果(每次运行各不相同(：

Before: MIRACULOUSNESS
After : MIRECULOUSNESS