unique values in array of objects only code example

Example 1: filter array with unique objects javascript

const array =
  [
    { "name": "Joe", "age": 17 },
    { "name": "Bob", "age": 17 },
    { "name": "Carl", "age": 35 }
  ]

const key = 'age';

const arrayUniqueByKey = [...new Map(array.map(item =>
  [item[key], item])).values()];

console.log(arrayUniqueByKey);

   /*OUTPUT
       [
        { "name": "Bob", "age": 17 },
        { "name": "Carl", "age": 35 }
       ]
   */

 // Note: this will pick the last duplicated item in the list.

Example 2: javascript get unique values from array

const myArray = [1,2,3,1,5,8,1,2,9,4];
const unique = [...new Set(myArray)]; // [1, 2, 3, 5, 8, 9, 4]

const myString = ["a","b","c","a","d","b"];
const uniqueString = [...new Set(myString)]; //["a", "b", "c", "d"]

Example 3: javascript get unique values from key

const unique = [...new Set(array.map(item => item.age))];

Example 4: how to create an array with unique values

import java.util.Random;

public class GenRandArray {
    //Recommend reseeding within methods
    static Random rand = new Random();

    public static void fillInt( int[] fillArray ) {
        //seeds the random for a new random each method call
        rand.setSeed(System.currentTimeMillis());
		
        for(int i = 0; i < fillArray.length; i++)
        {
            fillArray[i]= rand.nextInt();
            
          	/* for loop to check to make sure that none of the previous
               numbers added are the same as the one just added. */
            for (int j = 0; j < i; j++)
            {
              	/* if so we need to redo the last random number by
              	   moving i back one index to be re-set */
                if (fillArray[i] == fillArray[j])
                {
                    i--;
                }
            }
        }
    }
}