remove duplicates from a randomly selected array

Question

I have the following code which tries to remove duplicates from a randomly selected array items but it did'nt work,

items[] is the array containing its and i have usea sript to remove duplicates.

how do i change it to remove duplicates

what is the mistake?

window.onload = rnumber();
function rnumber() {
  const
    items = [  
      { label: '1', url: '1.jpg'  },
      { label: '2', url: '2.jpg'  },
      { label: '3', url: '3.jpg'  },
      { label: '4', url: '4.jpg'  },
      { label: '5', url: '5.jpg'  },
      { label: '6', url: '6.jpg'  },
      { label: '7', url: '7.jpg'  },
      { label: '8', url: '8.jpg'  },
      { label: '9', url: '9.jpg'  },
      { label: '10',url: '10.jpg' }
          ];

  
var lastnumber=0;
for (let index = 0; index < 9; index++) 
  {
      randomIndex = Math.floor(Math.random() * items.length);
      
  if(lastnumber!=randomIndex)
  {
      item = items[randomIndex];
      lastnumber=randomIndex;
   
   console.log(randomIndex);
   }
   else
   {
   rnumber()
   }
     
  }

}

remove comma after array and put semicolon there. its throws error. — Arif Rathod, Sep 18 '18 at 05:29
Possible duplicate of [Get all unique values in a JavaScript array (remove duplicates)](https://stackoverflow.com/questions/1960473/get-all-unique-values-in-a-javascript-array-remove-duplicates) — RoadEx, Sep 18 '18 at 07:20

Adrian Brand · Answer 1 · 2018-09-18T07:18:07.490

1

You can use reduce to get rid of duplicates

const distinctShuffle = array =>
  array ? array.reduce((arr, item) => {
    if (!(item in arr)) {
      arr.splice(Math.floor(Math.random() * (arr.length + 1)), 0, item);
    }
    return arr;
  }, []) : array;


function rnumber() {
  const items = [  
      { label: '1', url: '1.jpg'  },
      { label: '2', url: '2.jpg'  },
      { label: '3', url: '3.jpg'  },
      { label: '4', url: '4.jpg'  },
      { label: '5', url: '5.jpg'  },
      { label: '6', url: '6.jpg'  },
      { label: '7', url: '7.jpg'  },
      { label: '8', url: '8.jpg'  },
      { label: '9', url: '9.jpg'  },
      { label: '10',url: '10.jpg' }
          ];

  
      return distinctShuffle(items);
}

console.log(rnumber());

edited Sep 18 '18 at 07:18

answered Sep 18 '18 at 06:15

Adrian Brand

20,384
4
39
60

but shuffling is not achieved – geek Sep 18 '18 at 06:30
is there a way to achieve shuffling in this selection – geek Sep 18 '18 at 06:32
You could change the function to insert the item at a random spot in the array rather than at the end or write a different shuffle funtion – Adrian Brand Sep 18 '18 at 06:52

score 0 · Answer 2 · answered Sep 18 '18 at 05:30

0

You have some syntax errors in your code. Watch out for using semicolons at the end of the statement - not commas.

If you're using ES6 you can write something like this:

let distinct = [...new Set(items.map(item => item.label))]

answered Sep 18 '18 at 05:30

Jonasz

21
2

This will result in keys list only, not object list. – Killer Death Sep 18 '18 at 05:55

score 0 · Answer 3 · answered Sep 18 '18 at 05:40

0

Use Following Simple Function to Remove Duplicates from array using jquery

var YourArray = [  
{ label: '1', url: '1.jpg'  },

{ label: '1', url: '2.jpg'  },

{ label: '3', url: '3.jpg'  },

{ label: '4', url: '4.jpg'  },

{ label: '1', url: '5.jpg'  },

{ label: '6', url: '6.jpg'  },

{ label: '1', url: '7.jpg'  },

{ label: '8', url: '8.jpg'  },

{ label: '9', url: '9.jpg'  },

{ label: '10',url: '10.jpg' }
          ];
   var SortedArray = YourArray.filter(
                 function(a){if (!this[a.label]) {this[a.label] = 1; return a;}},
                 {}
                );
                alert(JSON.stringify(SortedArray));

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

answered Sep 18 '18 at 05:40

Som

598
3
12

iS there a way i can remove it from random selection i have uses inside the for loop – geek Sep 18 '18 at 06:02
Means you want to select some values from Table[array] & then remove duplicate records from it? – Som Sep 18 '18 at 06:06
yes exactly, wait i editing my code please check and reply – geek Sep 18 '18 at 06:08
What is this for: this[a.label] = 1 – Killer Death Sep 18 '18 at 06:10
please check now, i want a 9 numbered array without duplicates – geek Sep 18 '18 at 06:11
In every iteration of filter function the value of array comes as a object in so I was took this[a.label] for comparison – Som Sep 18 '18 at 06:20
may i know how u will select random values? – Som Sep 18 '18 at 06:26

remove duplicates from a randomly selected array

3 Answers3