array.splice ignores one of the elements

Question

I am trying to delete all the zeros in the array nums but for some reason the splice() method ignores one of the zeros. Can you tell me what the reason is?

var deleteZeroes = function(nums) {
  
    for(var i=0 ; i<nums.length ; i++)
        {
            if(nums[i]===0)
                {
                  nums.splice(i,1)
               
                }
        }
       
      return nums
};

deleteZeroes([0,0,4,0,3])

The first item is zero. You remove it. Everything moves one place down. The first item is now zero. However, you increase `i` and check index `1` now. — VLAZ, Oct 12 '20 at 19:15
`[0,0,4,0,3].filter( el => el)` will filter all zeros `// --> [4,3]` — Mechanic, Oct 12 '20 at 19:18
An alternate way to make it work, is to iterate from the end in reverse, like `(var i=nums.length-1 ; i>=0 ; i--) { //same code you have...} ` — RPDP, Oct 12 '20 at 19:22
@Leonardo I am not trying to create a new array. I want the removal to be in place. — Zaid, Oct 12 '20 at 19:23

54ka · Answer 1 · 2021-07-23T09:45:59.783

1

The task can be performed using the filter() method

Example: 1

var deleteZeroes = function(nums) {
    var n = nums.filter(x => x !== 0);
    return n
};

console.log(deleteZeroes([0,0,4,0,3]));

Example: 2 (Short syntax)

var deleteZeroes = (nums) => (nums.filter(x => x));

console.log(deleteZeroes([0,0,4,0,3]));

edited Jul 23 '21 at 09:45

answered Oct 12 '20 at 19:22

54ka

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score 1 · Accepted Answer · answered Oct 12 '20 at 19:26

1

If you are not trying to create a new array and want to remove in the same array, an alternate way to make it work, is to iterate from the end in reverse, like

(var i=nums.length-1 ; i>=0 ; i--) { 
   //same code you have...
}

answered Oct 12 '20 at 19:26

RPDP

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array.splice ignores one of the elements

2 Answers2