Last active
February 5, 2021 16:57
-
-
Save bendc/da83fdac68a1095f3595 to your computer and use it in GitHub Desktop.
Remove duplicates from array
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
function removeDuplicates(arr) { | |
var clean = [] | |
var cleanLen = 0 | |
var arrLen = arr.length | |
for (var i = 0; i < arrLen; i++) { | |
var el = arr[i] | |
var duplicate = false | |
for (var j = 0; j < cleanLen; j++) { | |
if (el !== clean[j]) continue | |
duplicate = true | |
break | |
} | |
if (duplicate) continue | |
clean[cleanLen++] = el | |
} | |
return clean | |
} |
Quick followup: the following usage of Set
seems to be faster than my method for arrays larger than ~130 elements.
var set = new Set(arr)
var clean = []
set.forEach(function(el) { clean.push(el) })
Thank you
Thank you
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Set
can be used to improve the performance of a uniqing function by loading it up with values, useset.add(v)
instead ofnew Set(array)
for a wider range of support, and then checking if the value exists in your loop,set.has(v)
, instead of using anindexOf
linear search equiv.There is a cost to creating and populating the set so I usually don't kick in the set optimization until an array is considered large enough to outweigh the cost, in my case
200
, but mileage will vary on your implementation.Set
is great for uniqing objects but not so great at primitives. Since uniqing numbers is a common case I special case numbers using an hash map for better performance.