Javascript - Remove duplicate arrays from a set
I have an array of arrays.
let myArr = [[1,2,3],[1,2,3],[3,4,5],[5,6,7],[5,6,7]];
I want to filter all repeating arrays in myArr so it stores only unique ones:
let myArr = [[1,2,3],[3,4,5],[5,6,7]];
I thought that by converting myArr into a set it would clear all 'duplicate' values, however, it did not:
let mySet = new Set(myArr);
// Set is: {[1,2,3],[1,2,3],[3,4,5],[5,6,7],[5,6,7]}
How can I properly filter myArr to hold only unique elements?
javascript arrays duplicates set
asked Nov 21 '18 at 20:51
EDJEDJ
193215
add a comment |
I have an array of arrays.
let myArr = [[1,2,3],[1,2,3],[3,4,5],[5,6,7],[5,6,7]];
I want to filter all repeating arrays in myArr so it stores only unique ones:
let myArr = [[1,2,3],[3,4,5],[5,6,7]];
I thought that by converting myArr into a set it would clear all 'duplicate' values, however, it did not:
let mySet = new Set(myArr);
// Set is: {[1,2,3],[1,2,3],[3,4,5],[5,6,7],[5,6,7]}
How can I properly filter myArr to hold only unique elements?
javascript arrays duplicates set
asked Nov 21 '18 at 20:51
EDJEDJ
193215
1
equality for arrays is not well defined, for example, are these "equal":[1,2,3] vs [1,,2,,3]? Or[1,"2"] vs ["1",2]?
– georg
Nov 21 '18 at 21:06
add a comment |
I have an array of arrays.
let myArr = [[1,2,3],[1,2,3],[3,4,5],[5,6,7],[5,6,7]];
I want to filter all repeating arrays in myArr so it stores only unique ones:
let myArr = [[1,2,3],[3,4,5],[5,6,7]];
I thought that by converting myArr into a set it would clear all 'duplicate' values, however, it did not:
let mySet = new Set(myArr);
// Set is: {[1,2,3],[1,2,3],[3,4,5],[5,6,7],[5,6,7]}
How can I properly filter myArr to hold only unique elements?
javascript arrays duplicates set
asked Nov 21 '18 at 20:51
EDJEDJ
193215
I have an array of arrays.
let myArr = [[1,2,3],[1,2,3],[3,4,5],[5,6,7],[5,6,7]];
I want to filter all repeating arrays in myArr so it stores only unique ones:
let myArr = [[1,2,3],[3,4,5],[5,6,7]];
I thought that by converting myArr into a set it would clear all 'duplicate' values, however, it did not:
let mySet = new Set(myArr);
// Set is: {[1,2,3],[1,2,3],[3,4,5],[5,6,7],[5,6,7]}
How can I properly filter myArr to hold only unique elements?
javascript arrays duplicates set
javascript arrays duplicates set
asked Nov 21 '18 at 20:51
EDJEDJ
193215
asked Nov 21 '18 at 20:51
EDJEDJ
193215
asked Nov 21 '18 at 20:51
EDJEDJ
193215
asked Nov 21 '18 at 20:51
EDJEDJ
193215
asked Nov 21 '18 at 20:51
EDJEDJ
193215
193215
1
equality for arrays is not well defined, for example, are these "equal":[1,2,3] vs [1,,2,,3]? Or[1,"2"] vs ["1",2]?
– georg
Nov 21 '18 at 21:06
add a comment |
1
equality for arrays is not well defined, for example, are these "equal":[1,2,3] vs [1,,2,,3]? Or[1,"2"] vs ["1",2]?
– georg
Nov 21 '18 at 21:06
1
1
equality for arrays is not well defined, for example, are these "equal":
[1,2,3] vs [1,,2,,3]? Or [1,"2"] vs ["1",2]?– georg
Nov 21 '18 at 21:06
equality for arrays is not well defined, for example, are these "equal":
[1,2,3] vs [1,,2,,3]? Or [1,"2"] vs ["1",2]?– georg
Nov 21 '18 at 21:06
add a comment |
4 Answers
4
active
oldest
votes
You could take stringed arrays as value for the set and map then the arrays back.
var array = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]],
unique = Array.from(
new Set(array.map(a => JSON.stringify(a))),
json => JSON.parse(json)
);
console.log(unique);If you need the original arrays, then you could filter with a Set.
var array = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]],
unique = array.filter(
(s => a => (j => !s.has(j) || s.set(j))(JSON.stringify(a)))
(new Set)
);
console.log(unique);answered Nov 21 '18 at 20:54
Nina ScholzNina Scholz
193k15107178
add a comment |
You can use JSON to identify duplicates in a set and keep only the unique arrays in your list.
const elem_sets = new Set();
const result = arr.filter(item => !elem_sets.has(JSON.stringify(item)) ? elem_sets.add(JSON.stringify(item)) : false);
console.log(result);
answered Nov 21 '18 at 20:58
nitrodmrnitrodmr
16316
add a comment |
Try this:
function remove(myArr) {
let s = new Set(myArr);
let it = s.values();
return Array.from(it);
}
answered Nov 21 '18 at 20:55
AkramAkram
60231324
add a comment |
You can also solve this with a single Array.reduce where you group on the Array.toString():
const data = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]]
const r = Object.values(data.reduce((r,c) => (r[c.toString()] = c, r), {}))
console.log(r)answered Nov 21 '18 at 21:27
AkrionAkrion
9,54011224
add a comment |
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4 Answers
4
active
oldest
votes
4 Answers
4
active
oldest
votes
active
oldest
votes
active
oldest
votes
You could take stringed arrays as value for the set and map then the arrays back.
var array = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]],
unique = Array.from(
new Set(array.map(a => JSON.stringify(a))),
json => JSON.parse(json)
);
console.log(unique);If you need the original arrays, then you could filter with a Set.
var array = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]],
unique = array.filter(
(s => a => (j => !s.has(j) || s.set(j))(JSON.stringify(a)))
(new Set)
);
console.log(unique);answered Nov 21 '18 at 20:54
Nina ScholzNina Scholz
193k15107178
add a comment |
You could take stringed arrays as value for the set and map then the arrays back.
var array = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]],
unique = Array.from(
new Set(array.map(a => JSON.stringify(a))),
json => JSON.parse(json)
);
console.log(unique);If you need the original arrays, then you could filter with a Set.
var array = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]],
unique = array.filter(
(s => a => (j => !s.has(j) || s.set(j))(JSON.stringify(a)))
(new Set)
);
console.log(unique);answered Nov 21 '18 at 20:54
Nina ScholzNina Scholz
193k15107178
add a comment |
You could take stringed arrays as value for the set and map then the arrays back.
var array = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]],
unique = Array.from(
new Set(array.map(a => JSON.stringify(a))),
json => JSON.parse(json)
);
console.log(unique);If you need the original arrays, then you could filter with a Set.
var array = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]],
unique = array.filter(
(s => a => (j => !s.has(j) || s.set(j))(JSON.stringify(a)))
(new Set)
);
console.log(unique);answered Nov 21 '18 at 20:54
Nina ScholzNina Scholz
193k15107178
You could take stringed arrays as value for the set and map then the arrays back.
var array = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]],
unique = Array.from(
new Set(array.map(a => JSON.stringify(a))),
json => JSON.parse(json)
);
console.log(unique);If you need the original arrays, then you could filter with a Set.
var array = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]],
unique = array.filter(
(s => a => (j => !s.has(j) || s.set(j))(JSON.stringify(a)))
(new Set)
);
console.log(unique);var array = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]],
unique = Array.from(
new Set(array.map(a => JSON.stringify(a))),
json => JSON.parse(json)
);
console.log(unique);var array = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]],
unique = Array.from(
new Set(array.map(a => JSON.stringify(a))),
json => JSON.parse(json)
);
console.log(unique);var array = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]],
unique = array.filter(
(s => a => (j => !s.has(j) || s.set(j))(JSON.stringify(a)))
(new Set)
);
console.log(unique);var array = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]],
unique = array.filter(
(s => a => (j => !s.has(j) || s.set(j))(JSON.stringify(a)))
(new Set)
);
console.log(unique);answered Nov 21 '18 at 20:54
Nina ScholzNina Scholz
193k15107178
answered Nov 21 '18 at 20:54
Nina ScholzNina Scholz
193k15107178
answered Nov 21 '18 at 20:54
Nina ScholzNina Scholz
193k15107178
answered Nov 21 '18 at 20:54
Nina ScholzNina Scholz
193k15107178
193k15107178
add a comment |
add a comment |
You can use JSON to identify duplicates in a set and keep only the unique arrays in your list.
const elem_sets = new Set();
const result = arr.filter(item => !elem_sets.has(JSON.stringify(item)) ? elem_sets.add(JSON.stringify(item)) : false);
console.log(result);
answered Nov 21 '18 at 20:58
nitrodmrnitrodmr
16316
add a comment |
You can use JSON to identify duplicates in a set and keep only the unique arrays in your list.
const elem_sets = new Set();
const result = arr.filter(item => !elem_sets.has(JSON.stringify(item)) ? elem_sets.add(JSON.stringify(item)) : false);
console.log(result);
answered Nov 21 '18 at 20:58
nitrodmrnitrodmr
16316
add a comment |
You can use JSON to identify duplicates in a set and keep only the unique arrays in your list.
const elem_sets = new Set();
const result = arr.filter(item => !elem_sets.has(JSON.stringify(item)) ? elem_sets.add(JSON.stringify(item)) : false);
console.log(result);
answered Nov 21 '18 at 20:58
nitrodmrnitrodmr
16316
You can use JSON to identify duplicates in a set and keep only the unique arrays in your list.
const elem_sets = new Set();
const result = arr.filter(item => !elem_sets.has(JSON.stringify(item)) ? elem_sets.add(JSON.stringify(item)) : false);
console.log(result);
answered Nov 21 '18 at 20:58
nitrodmrnitrodmr
16316
answered Nov 21 '18 at 20:58
nitrodmrnitrodmr
16316
answered Nov 21 '18 at 20:58
nitrodmrnitrodmr
16316
answered Nov 21 '18 at 20:58
nitrodmrnitrodmr
16316
16316
add a comment |
add a comment |
Try this:
function remove(myArr) {
let s = new Set(myArr);
let it = s.values();
return Array.from(it);
}
answered Nov 21 '18 at 20:55
AkramAkram
60231324
add a comment |
Try this:
function remove(myArr) {
let s = new Set(myArr);
let it = s.values();
return Array.from(it);
}
answered Nov 21 '18 at 20:55
AkramAkram
60231324
add a comment |
Try this:
function remove(myArr) {
let s = new Set(myArr);
let it = s.values();
return Array.from(it);
}
answered Nov 21 '18 at 20:55
AkramAkram
60231324
Try this:
function remove(myArr) {
let s = new Set(myArr);
let it = s.values();
return Array.from(it);
}
answered Nov 21 '18 at 20:55
AkramAkram
60231324
answered Nov 21 '18 at 20:55
AkramAkram
60231324
answered Nov 21 '18 at 20:55
AkramAkram
60231324
answered Nov 21 '18 at 20:55
AkramAkram
60231324
60231324
add a comment |
add a comment |
You can also solve this with a single Array.reduce where you group on the Array.toString():
const data = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]]
const r = Object.values(data.reduce((r,c) => (r[c.toString()] = c, r), {}))
console.log(r)answered Nov 21 '18 at 21:27
AkrionAkrion
9,54011224
add a comment |
You can also solve this with a single Array.reduce where you group on the Array.toString():
const data = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]]
const r = Object.values(data.reduce((r,c) => (r[c.toString()] = c, r), {}))
console.log(r)answered Nov 21 '18 at 21:27
AkrionAkrion
9,54011224
add a comment |
You can also solve this with a single Array.reduce where you group on the Array.toString():
const data = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]]
const r = Object.values(data.reduce((r,c) => (r[c.toString()] = c, r), {}))
console.log(r)answered Nov 21 '18 at 21:27
AkrionAkrion
9,54011224
You can also solve this with a single Array.reduce where you group on the Array.toString():
const data = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]]
const r = Object.values(data.reduce((r,c) => (r[c.toString()] = c, r), {}))
console.log(r)const data = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]]
const r = Object.values(data.reduce((r,c) => (r[c.toString()] = c, r), {}))
console.log(r)const data = [[1, 2, 3], [1, 2, 3], [3, 4, 5], [5, 6, 7], [5, 6, 7]]
const r = Object.values(data.reduce((r,c) => (r[c.toString()] = c, r), {}))
console.log(r)answered Nov 21 '18 at 21:27
AkrionAkrion
9,54011224
edited Nov 21 '18 at 21:33
answered Nov 21 '18 at 21:27
AkrionAkrion
9,54011224
answered Nov 21 '18 at 21:27
AkrionAkrion
9,54011224
answered Nov 21 '18 at 21:27
AkrionAkrion
9,54011224
9,54011224
add a comment |
add a comment |
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equality for arrays is not well defined, for example, are these "equal":
[1,2,3] vs [1,,2,,3]? Or[1,"2"] vs ["1",2]?– georg
Nov 21 '18 at 21:06