Move element of array to specific position

Question

How to move element of array to specific position on Android JAVA. We have

int oldPosition, int newPosition

and some like

JSONObject[] tmp = new JSONObject[999];

array of JSONObjects

Answer 1

If you want to just move tmp[newPosition]=tmp[oldPosition];

Swap

JSONObject jo= tmp[oldPosition]; tmp[oldPosition]=tmp[newPosition]; tmp[newPosition]=jo;

Answer 2

EDIT: There are other ways but you can go through this as well to get your result :)

Exercise : You can understand this logic and use JSONObject type and do necessary changes, Watch out for NullPointerExceptions , handle everything i am lazy to do them

let's say you have int array --> private int array[];

 array = new int[]{10,20,30,40,50,60,70,80,90,100};

call this method if you want to swap elements,

swapNumbers(array,9,1);

.

 public  int[]  swapNumbers(int [] arr, int possition1, int possition2){
    int temp  = arr[possition2];
    arr[possition2] = arr[possition1];
    arr[possition1] = temp;
    System.out.println("array -->" + Arrays.toString(array));
    return arr;
}

out put : array[10, 100, 30, 40, 50, 60, 70, 80, 90, 20]

---

But that doesn't satisfy you?

you need out put to be like this : array[10, 100, 20, 30, 40, 50, 60, 70, 80, 90]

you can use below method

resetUpMyArray(array, array[9],1);
System.out.println("array Finally changed-->" + Arrays.toString(array));

enjoy,

public int[] resetUpMyArray(int[] inputArray, int deleteMeValue,int addMePosition) {
            List resultLinkedList = new LinkedList();

            for (int itemValue : inputArray)
                if (deleteMeValue == itemValue) {
                    System.out.println("Do not add this value"+itemValue);
                } else {
                    System.out.println("Do add this value "+itemValue +"position-"+deleteMeValue);
                    resultLinkedList.add(itemValue);
                }

            System.out.println("array -as new L.L->" + resultLinkedList);
            resultLinkedList.add(addMePosition,deleteMeValue);
            System.out.println("array -as new L.L all set->" + resultLinkedList);

            array = new int[resultLinkedList.size()];
            for (int i = 0; i < resultLinkedList.size(); i++) {
                array[i] = (int) resultLinkedList.get(i); // Watch out for NullPointerExceptions!
            }

            return array;
        }

Answer 3

Here is two simple algorithm.

Switch values :

switch(array, from, to)
    tmp         = array[to]
    array[to]   = array[from]
    array[from] = tmp

That will give something like

[10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
          |--<---->--|
[10, 20, 60, 40, 50, 30, 70, 80, 90, 100]

This will simply store the values that will be replace at the index to to be place at index from

Move and shift values:

This one will move one values a shift the values next.

[10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
          |------------^
[10, 20,   , 40, 50, 60, 30, 70, 80, 90, 100]
           <-----------
[10, 20, 40, 50, 60, 30, 70, 80, 90, 100]

For this, the solution is quite the same, store the values in tmp but shift every value to fill the gap. This code will only work if from < to

tmp = array[to]    
i = from
while(i < to)
    array[i] = array[i+1]; --Shift the value
    i = i + 1       
array[to] = tmp;