CodeGym/Help with Java Tasks/Add 10 People to Map, and Add People With Same Last Name

Level 18

Grand Rapids

29.01.2019
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12comments

Add 10 People to Map, and Add People With Same Last Name

Question about the task

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I'm at a loss. As far as I can tell, I've met all of the conditions. Can anyone see why the third and fourth requirements are not being met?

1. Create a Map<String, String> and add 10 people represented by (last name, first name) pairs.
2. Among these 10 people, let there be people who share the same first names.
3. Among these 10 people, let there be people who share the same last names.
4. Display the contents of the Map on the screen.

Requirements:

The program should display text on the screen.
The Solution class must have only three methods.
The createPeopleMap() method must create and return a Map with (String, String) elements. Also, add 10 people to the map.
In the createPeopleMap() method, you need to add people with the same last name.
In the createPeopleMap() method, you need to add people with the same first name.
The printPeopleMap() method should display all people in the Map. Display each value on a new line. The last name and first name should be separated by a space.
The main() method should call the createPeopleMap() method.
The main() method should call the printPeopleMap() method.

package com.codegym.task.task08.task0821; import java.util.HashMap; import java.util.Map; /* Shared last names and first names */ public class Solution { public static Map<String, String> createPeopleList() { Map<String, String> people = new HashMap<String, String>() {{ put("Aaa", "Brian"); put("Bbb", "Casey"); put("Ccc", "Eliot"); put("Ddd", "Justin"); put("Eee", "Mitch"); put("Fff", "Tyler"); put("Ggg", "Tom"); put("Hhh", "Nick"); put("Iii", "Matt"); put("Jjj", "Lucas"); put("Aaa", "Tyler"); }}; return people; } public static void printPeopleList(Map<String, String> map) { for (Map.Entry<String, String> s : map.entrySet()) { System.out.println(s.getKey() + " " + s.getValue()); } } public static void main(String[] args) { Map<String, String> map = createPeopleList(); printPeopleList(map); } }

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Pavlo Plynko Java Developer at CodeGym

30 January 2019, 13:37

solution

Try to separate the creation of the collection and adding people.

Brian

Level 18 , Grand Rapids, United States

30 January 2019, 14:05

I get the same errors.

Pavlo Plynko Java Developer at CodeGym

30 January 2019, 14:14

Also call put() 10 times only, and some of them with same key.

Brian

Level 18 , Grand Rapids, United States

30 January 2019, 14:41

Applying both of these modifications works. Thanks.

Guadalupe Gagnon

Level 37 , Tampa, United States

29 January 2019, 14:09

solution

"2. Among these 10 people, let there be people who share the same first names. 3. Among these 10 people, let there be people who share the same last names."

Brian

Level 18 , Grand Rapids, United States

29 January 2019, 21:25

Can you be more specific? My code meets both of these conditions. I have two map entries with the last name "Aaa" and two map entries with the first name "Tyler". There isn't really a question of whether I have entries which share first names; the task verifier confirms as much.

Guadalupe Gagnon

Level 37 , Tampa, United States

29 January 2019, 21:32

Try the last two entries like this: put("Jjj", "Tyler"); put("Aaa", "Lucas"); Also remove one entry to make 10, you have 11.

Brian

Level 18 , Grand Rapids, United States

29 January 2019, 22:14

I get the same errors with this modification. The reason I have 11 implementations of the put method is that the second "Aaa" last name replaces the first entry with "Aaa" for the last name; thus, the map contains only 10 entries.

Guadalupe Gagnon

Level 37 , Tampa, United States

30 January 2019, 14:12

The specifications say put exactly ten in, not return a set with exactly ten. My solve has 9 people lines being printed to the screen

Guadalupe Gagnon

Level 37 , Tampa, United States

30 January 2019, 14:30

My only other suggestion would be not to add everyone during the map initialization. Maybe that is messing with the verification system? Try doing it like this:

Map<String, String> people = new HashMap<>();
   people.put("Aaa", "Brian");
   people.put("Bbb", "Casey");
   people.put("Ccc", "Eliot");
   people.put("Ddd", "Justin");
   people.put("Eee", "Mitch");
   people.put("Fff", "Tyler");
   people.put("Ggg", "Tom");
   people.put("Hhh", "Nick");
   people.put("Jjj","Tyler" );
   people.put("Aaa", "Lucas");

Brian

Level 18 , Grand Rapids, United States

30 January 2019, 14:40

Ok, I've got it now. Thanks for your help. It seems there were two issues. 1) I was returning 10 people, not 9. I think the instructions could use more clarity; I do not equate overriding an existing map entry with adding a new entry. Even though I called put() 11 times, I only added 10 people to the map. 2) You're right about the verification system. Creating the collection and adding people at the same time returns errors for the third and fourth requirements.

Guadalupe Gagnon

Level 37 , Tampa, United States

30 January 2019, 14:56

I encountered a lot of these issues, where my code worked according to the instructions, but failed verification because somewhere i implemented something a way that clashed with what was being tested. You're only level 9 now, expect plenty of head banging as you progress through. Ask for help anytime. I do my best to explain the problem, or if I don't see one, explain how my code differs from yours. Usually one of those will solve the issue at hand. Good luck with your continued learning, also, stay warm.