CODEWITHSUNDEEP
javaduplicateslinkedhashmap
Digitalwolf
Digitalwolf

Reputation: 493

duplicates for linkedhashmap

For the data that I am inputting into my program, I require duplicates, values for each item of data and I require the iteration order of the data to by insertion order as a default.

This is the kind of data that I am working with:

y = m * x + c
y = 8, m = 3, x = 2, c = 2

What I have been using up until now is a linkedHashMap to store all my data, which satisfies all my criteria other than storing duplicates.

So if I had b + b = c I wouldn't be able to get my program to work.

Preferably I would like to continue using maps for the key and value property and the ability to store different kinds if data i.e. String, Integer. So I would prefer a way for a linkedhashmap to retain duplicates. If there isn't, please let me know if there is any other way I can meet all my requirements.

Regards

Upvotes: 2

Views: 6216

Answers (3)

Mirko Adari
Mirko Adari

Reputation: 5103

Use Guava library Multimap with value type of Object. Check their documentation for more info.


  Multimap map = ArrayListMultimap.create();
  map.put(key, value1);
  map.put(key, value2);
  List values = map.get(key);

Upvotes: 1

Partha Pal
Partha Pal

Reputation: 308

You can use Map<Integer,List<Integer>> . In this datatype , you can store multiple values for the same key.Your put method can be like this ... 

    public void put(Integer key,Integer val){
     List<Integer> arr = map.get(key);
     if(arr == null){
      arr = new ArrayList<Integer>();
      map.put(key,arr);
     }
     arr.add(val);
    }

Upvotes: 1

Batakj
Batakj

Reputation: 12743

package com.shashi.mpoole;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.lang.reflect.Field;
import java.net.URISyntaxException;

public class LinearEquation {

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


        LinearEquation linearEquation = new LinearEquation();
         InputStream in = LinearEquation.class.getResourceAsStream("../../../Inputs.txt");

            // Inputs Taken
            try {
                // Reading Inputs
                BufferedReader reader=new BufferedReader(new InputStreamReader(in));
                String line=null;
                // Separated by Comma m=4,x=2,c=5
                    while((line=reader.readLine())!=null){
                        LinearEqInput lei = new LinearEqInput();
                        String[] inputs = line.split(",");
                        //Getting array [m=4,x=2,c=5]
                        for (int i = 0; i < inputs.length; i++) {

                            String[] keyval = inputs[i].split("=");
                            //Getting vallue [m,4]
                            linearEquation.setValue(lei, keyval[0], keyval[1]);

                        }
                        System.out.print("[Inputs: m= " + lei.m + " x= " + lei.x + " ,c= " + lei.c + "]");
                        //result
                        System.out.println(" Output :" + linearEquation.calculate(lei));

                    }
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }


    }

    // This method use reflection to store the value of a field in the class LinearEqInput
    public void setValue(LinearEqInput lei,String fieldName, String value) throws SecurityException, NoSuchFieldException, IllegalArgumentException, IllegalAccessException
    {
        Field f = lei.getClass().getDeclaredField(fieldName);
        f.setDouble(lei, Double.parseDouble(value));

    }

    //Calculating the Y
    public double calculate(LinearEqInput lei)
    {
        return lei.m*lei.x + lei.c;
    }



}



class LinearEqInput
{
//Inputs
    double m,x,c = 0;

}

Inputs File

m=4,x=3,c=1
m=4,x=4,c=6
m=4,x=5,c=5
m=4,x=7,c=4
m=4,x=2,c=3
m=4,x=5,c=2

Output:

[Inputs: m= 4.0 x= 3.0 ,c= 1.0] Output :13.0
[Inputs: m= 4.0 x= 4.0 ,c= 6.0] Output :22.0
[Inputs: m= 4.0 x= 5.0 ,c= 5.0] Output :25.0
[Inputs: m= 4.0 x= 7.0 ,c= 4.0] Output :32.0
[Inputs: m= 4.0 x= 2.0 ,c= 3.0] Output :11.0
[Inputs: m= 4.0 x= 5.0 ,c= 2.0] Output :22.0

Upvotes: 1

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