var arr = [-3, -34, 1, 32, -100];
How can I remove all items and just leave an empty array?
And is it a good idea to use this?
arr = [];
Thank you very much!
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4You answered your own question, at least the first one!Stephen– Stephen2010-08-27 16:17:45 +00:00Commented Aug 27, 2010 at 16:17
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possible duplicate of How to empty an array in JavaScript?Abid Rahman K– Abid Rahman K2013-04-25 17:54:22 +00:00Commented Apr 25, 2013 at 17:54
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2Possible duplicate of How do I empty an array in JavaScript?Mohammad Usman– Mohammad Usman2017-11-16 08:06:55 +00:00Commented Nov 16, 2017 at 8:06
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8 Answers
If there are no other references to that array, then just create a new empty array over top of the old one:
array = [];
If you need to modify an existing array—if, for instance, there's a reference to that array stored elsewhere:
var array1 = [-3, -34, 1, 32, -100];
var array2 = array1;
// This.
array1.length = 0;
// Or this.
while (array1.length > 0) {
array1.pop();
}
// Now both are empty.
assert(array2.length == 0);
Comments
the simple, easy and safe way to do it is :
arr.length = 0;
making a new instance of array, redirects the reference to one another new instance, but didn't free old one.
1 Comment
Pedro Ferreira
but didn't free old one. - Perfect! Tx @a.boussemaThese are the ways to empty an array in JavaScript
arr = [];arr.splice(0, arr.length);arr.length = 0;
Comments
one of those two:
var a = Array();
var a = [];
Just as you say:
arr = [];
Comments
Using arr = []; to empty the array is far more efficient than doing something like looping and unsetting each key, or unsetting and then recreating the object.
Comments
Out of box idea:
while(arr.length) arr.pop();
1 Comment
Tim Down
Will work, but is needlessly inefficient.
arr.length = 0 will be quicker and easier to read.Ways to clean/empty an array
- This is perfect if you do not have any references from other places. (substitution with a new array)
arr = []
- This Would not free up the objects in this array and may have memory implications. (setting prop length to 0)
arr.length = 0
- Remove all elements from an array and actually clean the original array. (splicing the whole array)
arr.splice(0,arr.length)
