Been stuck for three days....

Question about the task

Under discussion

My aim is to iterate through the values (Date objects) of the hashmap, convert them into Strings, then remove any that contain the three months. Please help.

Create a Map<String, Date> and add ten entries that represent (last name, birth date) pairs.
Remove from the map all people born in the summer.
Hint: At CodeGym, summer lasts from June 1 to August 31.

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, Date) elements and contains 10 entries.
The removeAllSummerPeople() method should remove from the map all people born in the summer.

package com.codegym.task.task08.task0816; import java.text.DateFormat; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Date; import java.util.HashMap; import java.util.Locale; import java.util.Calendar; import java.util.Iterator; import java.util.Map; public class Solution { public static HashMap<String, Date> createMap() throws ParseException { DateFormat df = new SimpleDateFormat("MMMMM d yyyy", Locale.ENGLISH); HashMap<String, Date> map = new HashMap<String, Date>(); map.put("Stallone", df.parse("JUNE 1 1980")); //REMOVE map.put("Lee", df.parse("OCTOBER 20 1994")); map.put("Johnson", df.parse("OCTOBER 10 1994")); map.put("May", df.parse("DECEMBER 31 1950")); map.put("Cameron", df.parse("DECEMBER 20 1960")); map.put("Brown", df.parse("DECEMBER 5 1960")); map.put("Blair", df.parse("JULY 28 1950")); //REMOVE map.put("Major", df.parse("FEBRUARY 10 1940")); map.put("Thatcher", df.parse("MARCH 11 1960")); map.put("Callaghan", df.parse("AUGUST 31 1920")); //REMOVE return map; } public static void removeAllSummerPeople(HashMap<String, Date> map) { Iterator <String> i = map.keySet().iterator(); while (i.hasNext()){ String value = (pair.getValue(it.next())); if (value.contains("JUNE") | (value.contains("JULY") | (value.contains("AUGUST")))){ i.remove(); } } } public static void main(String[] args) throws ParseException { removeAllSummerPeople(createMap()); } }

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Stephen noland

Level 17 , United States, United States

22 July 2020, 01:34

This is how i did it.

Maxine Hammett

Level 19 , San Diego, United States

21 July 2020, 03:06

I handled the code differently. I created a new hashcode map and cycled through it checking if the map contained the month.

public static void removeAllSummerPeople(HashMap<String, Date> map) {
     HashMap<String, Date> copy = new HashMap<String, Date>(map);
     for (Map.Entry<String, Date> pair : copy.entrySet()) {
         String value = pair.getValue().toString();
         if (value.contains("Jun") || value.contains("Aug") || value.contains("Jul")) {
             map.remove(pair.getKey());
         }
     }
 }

Mankin Lee

Level 9 , Manchester, United Kingdom

21 July 2020, 11:03

Getting this error: "cannot find symbol symbol: method entryset() location: variable copy of type java.util.HashMap<java.lang.String,java.util.Date>. file com/codegym/task/task08/task0816/Solution.java, line 32, position 1331"

Mankin Lee

Level 9 , Manchester, United Kingdom

21 July 2020, 12:48

package com.codegym.task.task08.task0816; import java.text.DateFormat; import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Date; import java.util.HashMap; import java.util.Locale; import java.util.Calendar; import java.util.Iterator; import java.util.Map; public class Solution { public static HashMap<String, Date> createMap() throws ParseException { DateFormat df = new SimpleDateFormat("MMMMM d yyyy", Locale.ENGLISH); HashMap<String, Date> map = new HashMap<String, Date>(); map.put("Stallone", df.parse("JUNE 1 1980")); //REMOVE map.put("Lee", df.parse("OCTOBER 20 1994")); map.put("Johnson", df.parse("OCTOBER 10 1994")); map.put("May", df.parse("DECEMBER 31 1950")); map.put("Cameron", df.parse("DECEMBER 20 1960")); map.put("Brown", df.parse("DECEMBER 5 1960")); map.put("Blair", df.parse("JULY 28 1950")); //REMOVE map.put("Major", df.parse("FEBRUARY 10 1940")); map.put("Thatcher", df.parse("MARCH 11 1960")); map.put("Callaghan", df.parse("AUGUST 31 1920")); //REMOVE return map; } public static void removeAllSummerPeople(HashMap<String, Date> map) { HashMap<String, Date> copy = new HashMap<String, Date>(map); for (Map.Entry<String, Date> pair : copy.entryset()) { String value = pair.getValue().toString(); if ((value.contains("JUNE") || (value.contains("JULY") || (value.contains("AUGUST"))))){ map.remove(); } } } public static void main(String[] args) throws ParseException { removeAllSummerPeople(createMap()); } }

Maxine Hammett

Level 19 , San Diego, United States

21 July 2020, 14:27

This is my code.

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.*;
import java.io.*;

/*
Kind Emma and the summer holidays

*/

public class Solution {
    public static HashMap<String, Date> createMap() throws ParseException {
        DateFormat df = new SimpleDateFormat("MMMMM d yyyy", Locale.ENGLISH);
        HashMap<String, Date> map = new HashMap<String, Date>();
        map.put("Stallone1", df.parse("JUNE 1 1980"));
        map.put("Mary", df.parse("AUGUST 1 1980"));
        map.put("Maxne", df.parse("JUNE 1 1980"));
        map.put("Mark", df.parse("OCTOBER 1 1980"));
        map.put("Missy", df.parse("SEPTEMBER 1 1980"));
        map.put("Nancy", df.parse("JULY 1 1980"));
        map.put("Jim", df.parse("APRIL 1 1980"));
        map.put("Matt", df.parse("MARCH 1 1980"));
        map.put("Mariah", df.parse("MAY 1 1980"));
        map.put("Bill", df.parse("JUNE 1 1980"));
        return map;
        //write your code here
    }

    public static void removeAllSummerPeople(HashMap<String, Date> map) {
        HashMap<String, Date> copy = new HashMap<String, Date>(map);
        for (Map.Entry<String, Date> pair : copy.entrySet()) {
            String value = pair.getValue().toString();
            if (value.contains("Jun") || value.contains("Aug") || value.contains("Jul")) {
                map.remove(pair.getKey());
            }
        }


    }

    public static void main(String[] args) throws Exception {

    }
}

Stephen noland

Level 17 , United States, United States

21 July 2020, 00:26

in the main method create a new hashmap then use the putall(createMap()) function. Then you call removeAllSummerPeople. HashMap<String, Date> hm = new HashMap<String, Date>(); hm.putAll(createMap()); removeAllSummerPeople(hm);