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RoyalUp
Asked: 2022-08-05 03:06:57 +0800 CST 2022-08-05 03:06:57 +0800 CST

Remove duplicate elements from a map

  • 772

For example I have this:

{[dificultad, adios]=["baja", "a"], 
 [dificultad, adios]=["baja", "a"], 
 [dificultad, adios]=["alta", "abckdk"]}

that is, a Map<List<String>, List<String>>, what I want to do and I can't do is, for example, if in the map, if there are identical keys and values ​​that are deleted and there is only one element of them.

Expected output:

{[dificultad, adios]=["baja", "a"], [dificultad, adios]=["alta", "abckdk"]}
java

1 Answers

  1. Best Answer

    Let's see if it serves as an example

    It does not correspond exactly to your problem, since I would be missing the classes to be able to complete your code, but it is an example that can give you an idea of ​​how to approach it

    I limit myself to using a two String value key HashMap, with a duplicate value, since the key of a HashMap has to be unique. In your case you don't use a simple HashMap key value, so it allows you to have duplicate keys.

    I put the code

    public static void main(String[] args){
    HashMap datos = new HashMap();

    // Añadimos datos a nuestro hashMap
    datos.put("Nombre","Fernando");
    datos.put("Apellido1","Guiado");
    datos.put("Apellido2","Gutiérrez");
    datos.put("Apellido3","Gutiérrez");

    //Declaramos un iterador para recorrer el contenido del HashMap
    Iterator it = datos.entrySet().iterator();
    
    System.out.println("Mostramos el contenido del HashMap: ");
    while (it.hasNext()) {
        Map.Entry e = (Map.Entry)it.next();
        System.out.println("Clave: " + e.getKey() + "          Valor: " + e.getValue());
    }
    
    int n = 0;
    
    System.out.println("--------------------------------------------------");
    System.out.println("--------------------------------------------------");

    System.out.println("Mostramos el contenido del nuevo HashMap con el valor duplicado eliminado: ");
    //declaramos un primer bucle para recorrer las key del hashmap hm
    for (Object key1:datos.keySet())
    {
        //en un segundo bucle volvemos a recorrer las key sobre el primero
        for (Object key2:datos.keySet()) 
        {
            //si la primera key es distinta a la segunda (No puede haber dos keys iguales)
            if (!key1.toString().equals(key2.toString())) 
            {
                //almacena el contenido en x del a primera key
                Object x = datos.get(key1);
                //almaena el contenido en y de la segunda key
                Object y = datos.get(key2);
                //si los contenidos de x e y son iguales
                if(x.equals(y)) {
                    //eliminas la segunda
                    datos.remove(key2);     
                    Iterator itE = datos.entrySet().iterator();
                    while (itE.hasNext()) {
                        Map.Entry e = (Map.Entry)itE.next();
                        System.out.println("Clave: " + e.getKey() + "          Valor: " + e.getValue());
                    }
                    //damos un valor para el if cualquiera
                    n = 10;
                    //salimos del for
                    break;
                }
            }
        }
        //si se cumple el valor que dimos
        if (n == 10){
            //salimos del primer for
            break;
        }
    }
    System.out.println("--------------------------------------------------");
    System.out.println("--------------------------------------------------");
}
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