Question

我被要求编写一个代码，该代码在一些条件下将元素添加到数组中。我在整个StackOverflow上进行了搜索，以查找如何在数组中查找元素，但是都给了我错误，所以我猜我的代码有问题，我无法弄清楚是什么。任何帮助表示赞赏。

public class WordList
{
    String [] words;
    int count = 0;
    int max = 2;

    WordList()
    {
        words = new String[max];
        this.words = words;
        this.count = count;
    }

    public static void main (String[] args)
    {
        WordList w1 = new WordList();
        System.out.println(w1.addWord("Dog"));
        System.out.println(w1.addWord("Cat"));
        System.out.println(w1.addWord("Fish"));
    }

    public int addWord(String newWord)
    {

        for(int i = 0; i < words.length; i++)
        {
            if(words.contains(newWord) == false && words.length < max)
            {
                words[i] = newWord;
            }
            else if(words.contains(newWord) == false && words.length == max)
            {
                max *= 2;
                words[i] = newWord;
            }



            count = i + 1;
        }
        return count;
    }

Answer 1

我认为您可以使用Set代替数组。

public class WordList {

    private final Set<String> words = new HashSet<>();

    public int addWord(String word) {
        if (word != null)
            words.add(word);
        return words.size();
    }

    public static void main(String[] args) {
        WordList w1 = new WordList();
        System.out.println(w1.addWord("Dog"));
        System.out.println(w1.addWord("Cat"));
        System.out.println(w1.addWord("Fish"));
    }
}

Answer 2

我认为这就是您想要做的。常规数组没有indexOf或contains方法，因此您需要使用Arrays（确保也将其导入）

public int addWord(String newWord)
{
  List <String> myList = Arrays.asList(words);

    for(int i = 0; i < words.length; i++)
    {
        if(myList.indexOf(newWord) == -1 && words.length < max)
        {
            words[i] = newWord;
        }
        else if(myList.indexOf(newWord) == -1 && words.length == max)
        {
            max *= 2;
            words[i] = newWord;
        }

        count = i + 1;
    }
    return count;
}

Answer 3

以任何方式，您都需要编写自己的方法来查找它。它不限于内存-您可以将数组转换为List并使用.contains（）方法。

Arrays.asList(words).contains(newWord);

否则，您可以使用流来查找元素。

Arrays.stream(words).anyMatch(newWord::equals);

Answer 4

我认为您正在寻找类似的解决方案，但这是使用ArrayList而不是Array。数组没有默认的contains方法，因此您需要实现自己的方法。

import java.util.ArrayList;
import java.util.List;

public class WordList {
    private static List<String> words = new ArrayList<>();

    public void addWord(String word) {
        if (!words.contains(word)) {
            words.add(word);
        }
    }

    public static List<String> getWords() {
        return words;
    }

    public static void main(String... args) {
        WordList instance = new WordList();
        instance.addWord("Dog");
        instance.addWord("Cat");
        instance.addWord("Fish");

        System.out.println(instance.getWords());
    }
}

Answer 5

错误在words.contains(newWord)

中

找不到符号符号：方法contains（String）位置： String []
类型的可变词

它可以通过更改代码来解决-

Arrays.asList(words).contains(newWord)而不是words.contains(newWord)。

请记住，您将需要导入java.util.Arrays

完整代码-

import java.util.Arrays;

/**
 *
 * @author pronet
 */
public class WordList
{
    String [] words;
    int count = 0;
    int max = 2;

    WordList()
    {
        words = new String[max];
        this.words = words;
        this.count = count;
    }

    public static void main (String[] args)
    {
        WordList w1 = new WordList();
        System.out.println(w1.addWord("Dog"));
        System.out.println(w1.addWord("Cat"));
        System.out.println(w1.addWord("Fish"));
    }

    public int addWord(String newWord)
    {
        for(int i = 0; i < words.length; i++)
        {
            if(Arrays.asList( words ).contains(newWord) == false && words.length < max)
            {
                words[i] = newWord;
            }
            else if(Arrays.asList( words ).contains(newWord) == false && words.length == max)
            {
                max *= 2;
                words[i] = newWord;
            }
            count = i + 1;
        }
        return count;
    }
 }

希望它可以为您提供帮助。

Answer 6

import java.util.HashSet;
import java.util.Set;

public class WordList {

    private final Set<String> words = new HashSet<>();

    public static void main(String[] args) {
        WordList w1 = new WordList();
        System.out.println(w1.addWord("Dog"));
        System.out.println(w1.addWord("Cat"));
        System.out.println(w1.addWord("Fish"));
    }

    public int addWord(String word) {
        words.add(word);
        return words.size();
    }

}

如何检查String []是否包含我的元素？

6 个答案: