Unable to remove array in javascript

Question

I have an of object, contains 5 element.

Now I loop through the to delete elements of which match with my condition.

for(var i = 0; i < items.length ; i++){
  console.log(i + '-'); //the result is 3-4
  if(_today.getTime() - items[i].timestamp >= numDay * ONE_DAY){
     console.log(i); //the result is 3
     items.splice(i,1);
  }
}

Sample of my array :

[{"DepartmentID":56,"CategoryID":117,"BrandID":19,"ID":707},
 {"DepartmentID":56,"CategoryID":117,"BrandID":19,"ID":708},
 {"DepartmentID":56,"CategoryID":117,"BrandID":19,"ID":709},
 {"DepartmentID":56,"CategoryID":117,"BrandID":19,"ID":710},
 {"DepartmentID":56,"CategoryID":117,"BrandID":19,"ID":711}]

The delete only one element in this for loop. Is it because of the index of problem and how could I delete n elements of the that match the condition in this loop?

Any help would be much appreciated, thank you..

Please give me that array too.

Fasil kk
– Fasil kk

2013-09-13 05:54:35 +00:00
Commented Sep 13, 2013 at 5:54 — Fasil kk
– Fasil kk, Commented Sep 13, 2013 at 5:54

Matt R. Wilson · Accepted Answer · 2013-09-13 05:57:19Z

2

When you modify an arrays size while looping it, you need to adjust your current index as you go. In your case whenever you splice off an item you need to --i;. This will back up your index by one and not cause your loop to skip an item.

answered Sep 13, 2013 at 5:57

Matt R. Wilson

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Comments

Rameez · Accepted Answer · 2013-09-13 06:01:37Z

0

This is because you using items.length to decide iterations for your loop and deleting it inside loop which changes length on every iteration you delete. You could manipulate copy of array inside loop instead then replace it in orignal one.

Something like this

var temp = items;

for(var i = 0; i < items.length ; i++){
  console.log(i + '-'); //the result is 3-4
  if(_today.getTime() - items[i].timestamp >= numDay * ONE_DAY){
     console.log(i); //the result is 3
     temp.splice(i,1);
  }
}

items= temp;

answered Sep 13, 2013 at 6:01

Rameez

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Comments

Dinesh · Accepted Answer · 2013-09-13 06:01:45Z

0

First, find the index of the element you want to remove:

var array = [2, 5, 9];
var index = array.indexOf(5);

Then remove it with splice:

if (index > -1) {
    array.splice(index, 1);
}

The second parameter of splice is the number of elements to remove. Note, splice modifies the array in place and returns an array with the elements you remove

answered Sep 13, 2013 at 6:01

Dinesh

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1 Comment

Vineeth Pradhan Over a year ago

I think this wouldn't work in case the array would have an Object. Consider this case var array = [{id: 1, title: "a1"}, {id: 2, title: "a2"}, {id: 1, title: "a1"}]. How would you delete an object with id: 2 and 3

Vineeth Pradhan · Accepted Answer · 2013-09-13 06:23:59Z

0

I found this solution in one of the jQuery plugins' source. items.splice(i--, 1); seems much simpler. This works only in case of deleting one item at a time from the array

for(var i = 0; i < items.length ; i++){
  if(_today.getTime() - items[i].timestamp >= numDay * ONE_DAY){
     items.splice(i--, 1);
  }
}

edited Sep 13, 2013 at 6:23

answered Sep 13, 2013 at 6:17

Vineeth Pradhan

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