Java 中的 2D LinkedList.contains()

发布于 2024-08-14 05:43:09 字数 561 浏览 1 评论 0 原文

嘿，大家。我是 Java 新手，我有这样的 2D LinkedList：

LinkedList> albums = new LinkedList>();

其中填充了如下数据：

if (!artist.isEmpty() && !name.isEmpty()) {
    albums.add(new LinkedList());
    albums.getLast().add(artist.toString());
    albums.getLast().add(name.toString());
}

但我想确保我的列表中没有重复的专辑。如何检查我的专辑列表是否已包含相同的艺术家和姓名？

原文

Hey, everyone. I'm new to Java and I have 2D LinkedList like this:

LinkedList<LinkedList<String>> albums = new LinkedList<LinkedList<String>>();

Which is filled with data like so:

if (!artist.isEmpty() && !name.isEmpty()) {
    albums.add(new LinkedList<String>());
    albums.getLast().add(artist.toString());
    albums.getLast().add(name.toString());
}

But I want to make sure my list has no duplicate albums. How to check whenever my albums list already contains same pair of artist and name?

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岁月如刀 2024-08-21 05:43:09

我的建议是创建一个名为 Album 的新类，看起来像这样：

public class Album
{
    private String name;
    private String artist;

    public Album(String name, String artist)
    {
        this.name = name;
        this.artist = artist;
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }

    public String getArtist()
    {
        return artist;
    }

    public void setArtist(String artist)
    {
        this.artist = artist;
    }

    public boolean equals(Object o)
    {
        if (o instanceof Album)
        {
            Album that = (Album)o;
            return album.equals(that.album) && artist.equals(that.artist);
        }
        else
        {
            return false;
        }
    }

    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((album == null) ? 0 : album.hashCode());
        result = prime * result + ((artist == null) ? 0 : artist.hashCode());
        return result;
    }
}

然后您应该能够使用 contains() 来检查专辑是否已存在于链接列表中。

My suggestion would be to create a new class, called Album that looks something like this:

public class Album
{
    private String name;
    private String artist;

    public Album(String name, String artist)
    {
        this.name = name;
        this.artist = artist;
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }

    public String getArtist()
    {
        return artist;
    }

    public void setArtist(String artist)
    {
        this.artist = artist;
    }

    public boolean equals(Object o)
    {
        if (o instanceof Album)
        {
            Album that = (Album)o;
            return album.equals(that.album) && artist.equals(that.artist);
        }
        else
        {
            return false;
        }
    }

    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((album == null) ? 0 : album.hashCode());
        result = prime * result + ((artist == null) ? 0 : artist.hashCode());
        return result;
    }
}

Then you should be able to use contains() to check whether or not the album already exists in the linked list.

回复收藏 0 原文

∞琼窗梦回ˉ 2024-08-21 05:43:09

是的，评论者说得对。创建一个包含 artist 和 name 字段的类 Album 并实现 equals() （和 hashCode() ）在他们身上。然后您可以使用 contains() 来查找重复项。或者甚至考虑使用 Set （但前提是散列代码确实在您的类上定义，因为集合是由散列支持的）。