CODEWITHSUNDEEP
java
Damien-Amen
Damien-Amen

Reputation: 7502

How to iterate through List in a hashmap value

I have a HashMap with String as key and List as value.

Name of the HashMap is pageMap.

Say this pageMap has the following key and value:

key = order
value = [page1, page2, page3]

now I want to display in the following pattern:

order
   page1
   page2
   page3

key2
   value1
   value2
   value3
   value4

Please tell me how do I do that?

Upvotes: 1

Views: 3224

Answers (4)

Slater Victoroff
Slater Victoroff

Reputation: 21914

public String formatDictionary(Map<String, List<String>> map){
    String output = '';
    for (String key : map.keySet()){
        output = output + key + "\n";
        for (String value: map.get(s)){
            output = output + "\t" + value + "\n";
    return output

Which is pretty similar to Jeppi's answer, but using string concatenation which is one of my favorite things about Java. I haven't run any benchmarks, but my guess is that his would be a little faster, but mine would have less overhead.

Upvotes: 0

Jens Piegsa
Jens Piegsa

Reputation: 7485

import java.util.*;
import java.lang.*;

public class StringListMapExample {

    public static String asTreeFormattedString(HashMap<String,List<String>> map) {
        final StringBuilder builder = new StringBuilder();
        for (String key : map.keySet()) {
            builder.append(key + "\n");
            for (String string : map.get(key)) {
                builder.append("\t" + string + "\n");
            }
        }
        return builder.toString();
    }

    public static void main(String[] args) {
        HashMap<String, List<String>> map = new HashMap<String, List<String>>();
        map.put("order", Arrays.asList(new String[]{"page1", "page2", "page3"}));
        System.out.println(asTreeFormattedString(map));
    }
}

Upvotes: 3

Amit
Amit

Reputation: 817

Iterate using iterator through all keys of hashmap using keyset()

{

  print key

  Iterate through value list using iterator

  {

   print each value

  }

}

Upvotes: 0

Has QUIT--Anony-Mousse
Has QUIT--Anony-Mousse

Reputation: 77454

Actually the solution is quite straightforward.

hashmap.get(key).iterator();

is an iterator for the list of the given key.

Why did you not try to figure it out yourself?

Upvotes: 0

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