I need to filter out my array to contain only unique values. this is my array data
["X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11"]
expected result should be
["X_row7", "X_row4", "X_row6", "X_row10", "X_row11", "X_row8", "X_row9"]
How should i continue my code to get proper result.
newArray = [];
for(n in data){
if(!newArray.indexOf(n)){
newArray.push(n);
}
}
console.log(newArray);
If you need any additional information's please let me know and i will provide. thank you
This question is related to
javascript
arrays
I've always used:
unique = (arr) => arr.filter((item, i, s) => s.lastIndexOf(item) == i);
But recently I had to get unique values for:
["1", 1, "2", 2, "3", 3]
And my old standby didn't cut it, so I came up with this:
uunique = (arr) => Object.keys(Object.assign({}, ...arr.map(a=>({[a]:true}))));
You can use Map and Spread Operator:
var rawData = ["X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11"];_x000D_
_x000D_
var unique = new Map();_x000D_
rawData.forEach(d => unique.set(d, d));_x000D_
var uniqueItems = [...unique.keys()];_x000D_
_x000D_
console.log(uniqueItems);
_x000D_
You could use a hash table for look up and filter all not included values.
var data = ["X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11"],_x000D_
unique = data.filter(function (a) {_x000D_
return !this[a] && (this[a] = true);_x000D_
}, Object.create(null));_x000D_
_x000D_
console.log(unique);
_x000D_
You can use reduce
to loop the array and get the not duplicate values. Also uses an aux object
to get the count of added values.
var aux = {};_x000D_
_x000D_
var newArray = ["X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11"].reduce((tot, curr)=>{_x000D_
if(!aux[curr]){_x000D_
aux[curr] = 1;_x000D_
tot.push(curr);_x000D_
}_x000D_
return tot;_x000D_
}, []);_x000D_
_x000D_
console.log(newArray);
_x000D_
Array.prototype.unique = function () {
return [...new Set(this)]
}
then we can write:
const arr = [1, 5, 2, 2, 2, 3, 4, 3, 2, 1, 5]
const uniqueArr = arr.unique()
Filtering an array to contain unique values can be achieved using the JavaScript Set and Array.from method, as shown below:
Array.from(new Set(arrayOfNonUniqueValues));
The Set object lets you store unique values of any type, whether primitive values or object references.
Return value A new Set object.
The Array.from() method creates a new Array instance from an array-like or iterable object.
Return value A new Array instance.
Example Code:
const array = ["X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11"]_x000D_
_x000D_
const uniqueArray = Array.from(new Set(array));_x000D_
_x000D_
console.log("uniqueArray: ", uniqueArray);
_x000D_
A slight variation on the indexOf
method, if you need to filter multiple arrays:
function unique(item, index, array) {
return array.indexOf(item) == index;
}
Use as such:
arr.filter(unique);
arr = ["I", "do", "love", "JavaScript", "and", "I", "also", "do", "love", "Java"];_x000D_
_x000D_
uniqueArr = [... new Set(arr)];_x000D_
_x000D_
// or_x000D_
_x000D_
reallyUniqueArr = arr.filter((item, pos, ar) => ar.indexOf(item) === pos)_x000D_
_x000D_
console.log(`${uniqueArr}\n${reallyUniqueArr}`)
_x000D_
This is for es2015
and above as far as I know. There are 'cleaner' options with ES6
but this a great way to do it (with TypeScript
).
let values: any[] = [];
const distinct = (value: any, index: any, self: any) => {
return self.indexOf(value) === index;
};
values = values.filter(distinct);
As of June 15, 2015 you may use Set()
to create a unique array:
var uniqueArray = [...new Set(array)]
For your Example:
var data = ["X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11"]
var newArray = [...new Set(data)]
console.log(newArray)
>> ["X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11"]
Source: Stackoverflow.com