Removing nested array with empty strings with underscore.js

Question

I have an array of arrays. Some of the arrays contain only a single empty string. I'd like to remove all of those from the parent array.

Before

[[ '*Order Number','*Line Number','*Item Number'],
[ '' ],
[ '018622','2','had-99']]

After

[[ '*Order Number','*Line Number','*Item Number'],
[ '018622','2','had-99']]

What if the array: ["abcd", "", "ijkl"]? Should it be removed? — ibrahim mahrir
– ibrahim mahrir, Commented Apr 28, 2017 at 19:56

Nina Scholz · Accepted Answer · 2017-04-28 20:05:19Z

3

You could use built in Array#filter for it.

var array = [[ '*Order Number','*Line Number','*Item Number'], [''], [ '018622','2','had-99']];

console.log(array.filter(function (a) { return a.toString(); }));

Version which mutates the original array.

var array = [[ '*Order Number','*Line Number','*Item Number'], [''], [ '018622','2','had-99']],
    i = array.length;

while (i--) {
    array[i].toString() || array.splice(i, 1);
}

console.log(array);

edited Apr 28, 2017 at 20:05

answered Apr 28, 2017 at 19:58

Nina Scholz

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2 Comments

Branndon Over a year ago

This works! It's ok that it returns a new array, a simple var order_array = array.filter(function (a) { return a.toString(); }); assigns it to what I need.

ibrahim mahrir Over a year ago

With arrow functions is just pure awesomeness array.filter(a => a + '');. +1!

theptrk · Accepted Answer · 2017-04-28 20:00:23Z

0

I'd probably check both that the array only has length 1 and that the item is an empty string

var list = [[ '*Order Number','*Line Number','*Item Number'], [''], [ '018622','2','had-99']];

list.filter(function(arr){
  if(arr.length === 1 && arr[0] === '') {
    return false;
  }
  return true;
}}

answered Apr 28, 2017 at 20:00

theptrk

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Comments

kind user · Accepted Answer · 2017-04-28 20:05:03Z

0

Better approach would be using Array#splice, which deletes specified elements from the parent array.

var arr = [[ '*Order Number','*Line Number','*Item Number'], [''], [ '018622','2','had-99']];

for (var i = 0; i < arr.length; i++) {
  if (arr[i][0] == '' && arr[i].length == 1) {
    arr.splice(i, 1);
    --i;
  }
}

console.log(arr);

answered Apr 28, 2017 at 20:05

kind user

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