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I have an array:
var a = [2,3,4,5,5,4]
I want to get unique array out of given array like
b = [2,3,4,5]
I have tried
a.filter(function(d){return b.indexOf(d)>-1})
and I don't want to use for loop.
813
To duplicate an array, just return the element in your map call. numbers = [1, 2, 3]; numbersCopy = numbers. map((x) => x); If you'd like to be a bit more mathematical, (x) => x is called identity.
Using the indexOf() method In this method, what we do is that we compare the index of all the items of an array with the index of the first time that number occurs. If they don't match, that implies that the element is a duplicate. All such elements are returned in a separate array using the filter() method.
Use the filter() method: The filter() method creates a new array of elements that pass the condition we provide. It will include only those elements for which true is returned. We can remove duplicate values from the array by simply adjusting our condition.
To remove the duplicates from an array of objects: Create an empty array that will store the unique object IDs. Use the Array. filter() method to filter the array of objects. Only include objects with unique IDs in the new array.
This is not an Angular related problem. It can be resolved in a couple of ways depending which libraries you are using.
If you are using jquery:
var uniqeElements = $.unique([2,3,4,5,5,4]);
The output would be:
[2,3,4,5]
If you are using underscore:
var uniqeElements = _.uniq([2,3,4,5,5,4]);
Same output.
And pure JS code:
var unique = [2,3,4,5,5,4].filter(function(elem, index, self) {
return index == self.indexOf(elem);
})
You can simply do it in JavaScript, with the help of the second - index - parameter of the filter method:
var a = [2,3,4,5,5,4];
a.filter(function(value, index){ return a.indexOf(value) == index });
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