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Courses Plus Student 1,172 Pointswhy am i getting this error?
i think i got it right. but im getting this annoying error:
" ./com/example/Blog.java:24: error: for-each not applicable to expression type for(String category : post.getCategory()){ ^ required: array or java.lang.Iterable found: String " somebody please help.
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;
}
}
package com.example;
import java.util.*;
import java.util.Set;
import java.util.TreeSet;
public class Blog {
List<BlogPost> mPosts;
public Blog(List<BlogPost> posts) {
mPosts = posts;
}
public List<BlogPost> getPosts() {
return mPosts;
}
public Map <String, Integer> getCategoryCounts()
{
Map <String, Integer> categoryCount = new HashMap <String, Integer>();
for (BlogPost post: mPosts) {
for(String category : post.getCategory()){
Integer count = categoryCount.get(category);
if (count == null) {
count = 0;
}
count++;
categoryCount.put(category, count);
}
System.out.println("category count" + categoryCount);
}
}
public Set<String> getAllAuthors() {
Set<String> authors = new TreeSet<>();
for (BlogPost post: mPosts) {
authors.add(post.getAuthor());
}
return authors;
}
}
1 Answer
Grigorij Schleifer
10,365 PointsHi mos,
lets take a look at your code:
public Map <String, Integer> getCategoryCounts(){
Map <String, Integer> categoryCount = new HashMap <String, Integer>();
// create a loop that loops over every post inside mPosts
// every post has a category, so you can count the number of categories
for (BlogPost post: mPosts) {
// so every "post" is equals one categry
// for(String category : post.getCategory()){
// no need for the second for-loop
Integer count = categoryCount.get(post.getCategory());
// create an integer to store the number of categories
// try to get the category out of your new Map
// at the beginning there are no categories inside
// getCategory will return null
if (count == null) {
// thats why set the count to 0
count = 0;
}
count++;
// next post inside the loop will check the second post
// so increase the count
// categoryCount.put(category, count); // deleted this line
categoryCount.put(post.getCategory(), count);
// put the category as key and count as value into the Map
// System.out.println("category count" + categoryCount);
// no need for printing the result
}
return categoryCount;
// but dont forget to return the Map because the method has a Map return type
}
And don´t forget to import Map and HashMap !
Makes sense?
Grigorij
mos per
Courses Plus Student 1,172 Pointsmos per
Courses Plus Student 1,172 PointsIngenuity!
Thanx a ton!
Grigorij Schleifer
10,365 PointsGrigorij Schleifer
10,365 PointsGlad I coukd help !
See you in the forum mos !