wherere is the problem?

Question about the task

Resolved

package com.codegym.task.task08.task0817;

import java.util.HashMap;
import java.util.Map;

/*
We don't need repeats

*/

public class Solution {
    public static HashMap<String, String> createMap() {
         HashMap<String,String> map = new HashMap<String,String>();
        map.put("Sayan","Samanta");
        map.put("Manika","Maiti");
        map.put("Anuva","Samanta");
        map.put("Sunil","Samanta");
        map.put("Sayan","ChowDhuri");
        map.put("Anurag","Diwedi");
        map.put("Youvraj","Patil");
        map.put("Bithika","Maiti");
        map.put("Manish","Maiti");
        map.put("Sourav","Saha");

        return map;

    }

they arwe saying put 10 entries there is 10 entry

Create a Map<String, String> and add ten entries that represent (last name, first name) pairs.
Remove people with the same first name.

Requirements:

The program should not display text on the screen.
The program should not read values from the keyboard.
The createMap() method must create and return a HashMap that has (String, String) elements and contains 10 entries.
The removeFirstNameDuplicates() method must remove from the map all people who have the same first name.
The removeFirstNameDuplicates() method must call the removeItemFromMapByValue() method.

package com.codegym.task.task08.task0817; import java.util.HashMap; import java.util.Map; /* We don't need repeats */ public class Solution { public static HashMap<String, String> createMap() { HashMap<String,String> map = new HashMap<String,String>(); map.put("Sayan","Samanta"); map.put("Manika","Maiti"); map.put("Anuva","Samanta"); map.put("Sunil","Samanta"); map.put("Sayan","ChowDhuri"); map.put("Anurag","Diwedi"); map.put("Youvraj","Patil"); map.put("Bithika","Maiti"); map.put("Manish","Maiti"); map.put("Sourav","Saha"); return map; } public static void removeTheFirstNameDuplicates(Map<String, String> map) { for(int i=0;i<10;i++){ if(map.get(i) == map.get(i+1)){ map.remove(i); } } } public static void removeItemFromMapByValue(Map<String, String> map, String value) { HashMap<String, String> copy = new HashMap<String, String>(map); for (Map.Entry<String, String> pair : copy.entrySet()) { if (pair.getValue().equals(value)) map.remove(pair.getKey()); } } public static void main(String[] args) { } }

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Anita Pal

Level 14 , India

31 October 2019, 07:39

In if condition when you reach to last index ,there will be no further index to compare,so it will give error

Roman

Level 41

30 August 2018, 08:44

Try to create map and check size.

public static void main(String[] args) {
    HashMap map = createMap();
    System.out.println(map.size());
}

You will be surprised )