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javahashmap

How to iterate over object array from hashmap


I have two hashmap of type

Hashmap<String,Object[]> hasOne = new Hashmap<String,Object[]>();
Hashmap<String,Object[]> hasTwo = new Hashmap<String,Object[]>();

I've added values in both of them,

hasOne.put("anyKey", new Object[1,"Two",3.14]);
hasTwo.put("anyKey", new Object[1,"Two"]);

My requirement is I need to compare values from the object array of both hashmaps and need to print missing data from the object array of the second hashmap ( Ex. 3.14 is missing in the second array on comparing new Object[1,"Two",3.14] && new Object[1,"Two"] ).

Using Arrays.asList(hasOne.get("anyKey"));// will get details of object array but i'm not sure how to iterate over that array.

PFB code snippet

Map<String, Object[]> one = new HashMap<String, Object[]>();
Map<String, Object[]> two = new HashMap<String, Object[]>();
one.put("firstArray", new Object[]  {1, "Two", 3.14});
two.put("secondArray", new Object[] {1, "Two"});
for(int k=0;k<one.size();k++)
{   
    System.out.println(Arrays.asList(one.get("firstArray")));
}

Solution

  • Try this. References I used are :

    1. https://www.javatpoint.com/how-to-compare-two-arraylist-in-java
    2. Why do I get an UnsupportedOperationException when trying to remove an element from a List?
            // create and insert into maps
            Map<String, Object[]> one = new HashMap<String, Object[]>();
            Map<String, Object[]> two = new HashMap<String, Object[]>();
       
            one.put("firstArray", new Object[]  {1, "Two", 3.14});
            two.put("secondArray", new Object[] {1, "Two"});
    
            for(int k=0;k<one.size();k++)
            {
                List<Object> arrList1 = new ArrayList<>(Arrays.asList(one.get("firstArray"))); // get the value from the map "one" as arrayList
                List<Object> arrList2 = new ArrayList<>(Arrays.asList(two.get("secondArray"))); // get the value from the map "two" as arrayList
                // System.out.println(arrList1 + " " + arrList2);
                arrList1.removeAll(arrList2); // removes all different values as you require
                System.out.println(arrList1);
            }