How do I make a "for list/array loop"

Question

I have no idea what to put there in the array in Blog

com/example/BlogPost.java

package com.example;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;


public class BlogPost implements Comparable<BlogPost>, Serializable {
  private String mAuthor;
  private String mTitle;
  private String mBody;
  private String mCategory;
  private Date mCreationDate;

  public BlogPost(String author, String title, String body, String category, Date creationDate) {
    mAuthor = author;
    mTitle = title;
    mBody = body;
    mCategory = category;
    mCreationDate = creationDate;
  }

  public int compareTo(BlogPost other) {
    if (equals(other)) {
      return 0;
    }
    return mCreationDate.compareTo(other.mCreationDate);
  }

  public String[] getWords() {
    return mBody.split("\\s+");
  }

  public List<String> getExternalLinks() {
    List<String> links = new ArrayList<String>();
    for (String word : getWords()) {
      if (word.startsWith("http")) {
        links.add(word);
      }
    }
    return links;
  }

  public String getAuthor() {
    return mAuthor;
  }

  public String getTitle() {
    return mTitle;
  }

  public String getBody() {
    return mBody;
  }

  public String getCategory() {
    return mCategory;
  }

  public Date getCreationDate() {
    return mCreationDate;
  }
}

com/example/Blog.java

package com.example;

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

public class Blog {
  List<BlogPost> mPosts;
  public Blog(List<BlogPost> posts) {
    mPosts = posts;
  }

  public List<BlogPost> getPosts() {
    return mPosts;
  }

  public Set<String> getAllAuthors() {
    Set<String> allAuthors = new HashSet<String>();
    for(BlogPost authors : whatdoidohere) {
      allAuthors.addAll(authors.getAuthor());
    }
    return allAuthors;
  }
}

Answer 1 · 2017-10-02T17:05:56Z

October 2, 2017 5:05pm

You need to loop through all the blog posts. For each post, you add the author to the set. You're almost there :-) In your Blog class, you have a list of blog posts stored in the variable mPosts. That's what you should use in your loop.

Also you should use a TreeSet rather than a HashSet, because you want the authors to be sorted alphabetically. The TreeSet will keep the author names sorted.

  public Set<String> getAllAuthors() {
    Set<String> allAuthors = new TreeSet<String>();
    for (BlogPost post : mPosts) {
      allAuthors.add(post.getAuthor());
    }
    return allAuthors;
  }

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Kenzo Qui

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How do I make a "for list/array loop"

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Livia Galeazzi

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Kenzo Qui

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