CodeGym/Help with Java Tasks/HELP ME PLS GUYS

Level 22

Kharkiv

19.06.2019
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HELP ME PLS GUYS

Question about the task

Display a list of keys

Java Syntax, Level 8, Lesson 3

Under discussion

Give me solution pls(

There is a HashMap<String, String>. 10 different strings have been added to it.
Display a list of keys on the screen, each element on a new line.

Requirements:

The program must create a HashMap variable with (String, String) elements. The variable must be initialized immediately.
The program should not read values from the keyboard.
The program should add 10 different strings to the collection in accordance with the conditions.
The printKeys() method should display the keys in the collection, each element on a new line.

package com.codegym.task.task08.task0804; import java.util.HashMap; import java.util.Map; /* Display a list of keys */ public class Solution { public static void main(String[] args) throws Exception { HashMap<String, String> map = new HashMap<String, String>(); map.put("Sim", "Sim"); map.put("Tom", "Tom"); map.put("Arbus", "Arbus"); map.put("Baby", "Baby"); map.put("Cat", "Cat"); map.put("Dog", "Dog"); map.put("Eat", "Eat"); map.put("Food", "Food"); map.put("Gevey", "Gevey"); map.put("Hugs", "Hugs"); printKeys(map); } public static void printKeys(Map<String, String> map) { //write your code here HashMap<String, String> m = new HashMap<>(); for(HashMap.Entry<String,String> pair : map.entrySet()) System.out.println(map); } }

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Sherlockk

Level 9 , Kraków, Poland

18 June 2020, 14:48

Hi Denis, Inside of for loop before shows in System.out.println you could declare a String as value ( String value : pair.getValue(); ) Edit : You dont need to initialize new HashMap in method After it you could show value in System.out.println(value).

Saheb Das

Level 8 , Gurgaon, India

23 November 2019, 18:46

At line 30 you initialize a new hashmap. it's ok but missing the line in which all the data are copying from the "map" hashMap. for it, you should add a new line " m.putAll(map); ". The second problem is the printing problem. Here(at line 31) you use the "map" hashmap in the for loop. you should use the new hashmap. So this should be " for (Map.Entry<String, String> pair : m.entrySet()) ". and the very last line(32) print the keys only. It should like " System.out.println(pair.getKey()); ".

Laxman

Level 11 , indore, india

14 August 2019, 16:30

package com.codegym.task.task08.task0804; import java.util.HashMap; import java.util.Map; /* Display a list of keys */ public class Solution { public static void main(String[] args) throws Exception { HashMap<String, String> map = new HashMap<String, String>(); map.put("Sim", "Sim"); map.put("Tom", "Tom"); map.put("Arbus", "Arbus"); map.put("Baby", "Baby"); map.put("Cat", "Cat"); map.put("Dog", "Dog"); map.put("Eat", "Eat"); map.put("Food", "Food"); map.put("Gevey", "Gevey"); map.put("Hugs", "Hugs"); printKeys(map); } public static void printKeys(Map<String, String> map) { HashMap<String , String> m = new HashMap<>(); for(HashMap.Entry<String , String> pair : map.entrySet()) { String key = pair.getKey(); System.out.println(key); } } }

ardon polukoff

Level 9 , Lakeland, United States

13 November 2019, 22:14

Why are you declaring a new HasMap object called m within the function? You are not putting new key,value pairs into it.

Abraham

Level 22 , Watsonville, United States

19 June 2019, 22:14

print the pair.getKey() instead of the map. The pair variable is holding each key-value as it goes through the for loop.

Thomas Zehe

Level 17 , Berlin, Germany

19 June 2019, 19:08

You should display only the keys but you are printing the whole map.

Denis

Level 22 , Kharkiv, Ukraine

19 June 2019, 19:20

how i can do this?

Thomas Zehe

Level 17 , Berlin, Germany

19 June 2019, 19:26

map.keySet() gives you only the keys. Afterwards you can iterate over the keys and print each key.

Denis

Level 22 , Kharkiv, Ukraine

20 June 2019, 08:28

Last condition( package com.codegym.task.task08.task0805; import java.util.HashMap; import java.util.Map; /* Values on the screen! */ public class Solution { public static void main(String[] args) throws Exception { HashMap<String, String> map = new HashMap<String, String>(); map.put("Sim", "Sim"); map.put("Tom", "Tom"); map.put("Arbus", "Arbus"); map.put("Baby", "Baby"); map.put("Cat", "Cat"); map.put("Dog", "Dog"); map.put("Eat", "Eat"); map.put("Food", "Food"); map.put("Gevey", "Gevey"); map.put("Hugs", "Hugs"); printValues(map); } public static void printValues(Map<String, String> map) { //write your code here HashMap<String, String> m = new HashMap<>(); for(HashMap.Entry<String,String> pair : map.entrySet()) System.out.println(map.keySet()); } }

Thomas Zehe

Level 17 , Berlin, Germany

20 June 2019, 10:30

The printKeys() method should display the keys in the collection, each element on a new line. You are currently printing the whole key-set.

Denis

Level 22 , Kharkiv, Ukraine

20 June 2019, 10:37

give me full code pls for understanding

Thomas Zehe

Level 17 , Berlin, Germany

20 June 2019, 10:56

Just tell me how would you print the keys each on a new line? I can give you some hints: 1. get the keys: I already told you how to do it. map.keySet() returns a Set of the keys in the map 2. iterate over the set: You did the same thing above but there you are iterating over the Map.Entry<String, String> or the Pairs 3. print the specific key on a new line -> System.out.println(key) By just giving you the solution you will learn nothing and what's then the reason for you on staying here. You have some misunderstandings about the thing you should do and I try to help you in clarifying the task. But you have to code it yourself.