Can any one help me sort a 2 dimensional Array in JavaScript?
It will have data in the following format:
[12, AAA]
[58, BBB]
[28, CCC]
[18, DDD]
It should look like this when sorted:
[12, AAA]
[18, DDD]
[28, CCC]
[58, BBB]
So basically, sorting by the first column.
Cheers
It's this simple:
var a = [[12, 'AAA'], [58, 'BBB'], [28, 'CCC'],[18, 'DDD']];
a.sort(sortFunction);
function sortFunction(a, b) {
if (a[0] === b[0]) {
return 0;
}
else {
return (a[0] < b[0]) ? -1 : 1;
}
}
I invite you to read the documentation.
If you want to sort by the second column, you can do this:
a.sort(compareSecondColumn);
function compareSecondColumn(a, b) {
if (a[1] === b[1]) {
return 0;
}
else {
return (a[1] < b[1]) ? -1 : 1;
}
}
< or >. Anyways, I like the update :)The best approach would be to use the following, as there may be repetitive values in the first column.
var arr = [[12, 'AAA'], [12, 'BBB'], [12, 'CCC'],[28, 'DDD'], [18, 'CCC'],[12, 'DDD'],[18, 'CCC'],[28, 'DDD'],[28, 'DDD'],[58, 'BBB'],[68, 'BBB'],[78, 'BBB']];
arr.sort(function(a,b) {
return a[0]-b[0]
});
Try this:
//WITH FIRST COLUMN
arr = arr.sort((a, b) => a[0] - b[0]);
//WITH SECOND COLUMN
arr = arr.sort((a, b) => a[1] - b[1]);
Note: Original answer used a greater than (>) instead of minus (-) which is what the comments are referring to as incorrect.
Using the arrow function, and sorting by the second string field
var a = [[12, 'CCC'], [58, 'AAA'], [57, 'DDD'], [28, 'CCC'],[18, 'BBB']];
a.sort((a, b) => a[1].localeCompare(b[1]));
console.log(a)
collator.compareIf you're anything like me, you won't want to go through changing each index every time you want to change the column you're sorting by.
function sortByColumn(a, colIndex){
a.sort(sortFunction);
function sortFunction(a, b) {
if (a[colIndex] === b[colIndex]) {
return 0;
}
else {
return (a[colIndex] < b[colIndex]) ? -1 : 1;
}
}
return a;
}
var sorted_a = sortByColumn(a, 2);
in one line:
var cars = [
{type:"Volvo", year:2016},
{type:"Saab", year:2001},
{type:"BMW", year:2010}
]
function myFunction() {
return cars.sort((a, b)=> a.year - b.year)
}
If you want to sort based on first column (which contains number value), then try this:
arr.sort(function(a,b){
return a[0]-b[0]
})
If you want to sort based on second column (which contains string value), then try this:
arr.sort(function(a,b){
return a[1].charCodeAt(0)-b[1].charCodeAt(0)
})
P.S. for the second case, you need to compare between their ASCII values.
Nothing special, just saving the cost it takes to return a value at certain index from an array.
function sortByCol(arr, colIndex){
arr.sort(sortFunction)
function sortFunction(a, b) {
a = a[colIndex]
b = b[colIndex]
return (a === b) ? 0 : (a < b) ? -1 : 1
}
}
// Usage
var a = [[12, 'AAA'], [58, 'BBB'], [28, 'CCC'],[18, 'DDD']]
sortByCol(a, 0)
console.log(JSON.stringify(a))
// "[[12,"AAA"],[18,"DDD"],[28,"CCC"],[58,"BBB"]]"
a[colIndex] again and again but I am catching it here a = a[colIndex]. It's more efficient. 2. I am using different flavor of if, making it more shorter. 3. I am not returning arr as a result of sortByCol function which means my function can't be use to create another reference. Hope it helps!I use sort to sort the array
This is my code :
const sortArr = (arr) => {
arr.sort((valA, valB) => valA[0] - valB[0])
return arr
}
const arr = [
[12, 'AAA'],
[58, 'BBB'],
[28, 'CCC'],
[18, 'DDD']
]
console.log(sortArr(arr))
Standing on the shoulders of charles-clayton and @vikas-gautam, I added the string test which is needed if a column has strings as in OP.
return isNaN(a-b) ? (a === b) ? 0 : (a < b) ? -1 : 1 : a-b ;
The test isNaN(a-b) determines if the strings cannot be coerced to numbers. If they can then the a-b test is valid.
Note that sorting a column of mixed types will always give an entertaining result as the strict equality test (a === b) will always return false.
See MDN here
This is the full script with Logger test - using Google Apps Script.
function testSort(){
function sortByCol(arr, colIndex){
arr.sort(sortFunction);
function sortFunction(a, b) {
a = a[colIndex];
b = b[colIndex];
return isNaN(a-b) ? (a === b) ? 0 : (a < b) ? -1 : 1 : a-b ; // test if text string - ie cannot be coerced to numbers.
// Note that sorting a column of mixed types will always give an entertaining result as the strict equality test will always return false
// see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Equality_comparisons_and_sameness
}
}
// Usage
var a = [ [12,'12', 'AAA'],
[12,'11', 'AAB'],
[58,'120', 'CCC'],
[28,'08', 'BBB'],
[18,'80', 'DDD'],
]
var arr1 = a.map(function (i){return i;}).sort(); // use map to ensure tests are not corrupted by a sort in-place.
Logger.log("Original unsorted:\n " + JSON.stringify(a));
Logger.log("Vanilla sort:\n " + JSON.stringify(arr1));
sortByCol(a, 0);
Logger.log("By col 0:\n " + JSON.stringify(a));
sortByCol(a, 1);
Logger.log("By col 1:\n " + JSON.stringify(a));
sortByCol(a, 2);
Logger.log("By col 2:\n " + JSON.stringify(a));
/* vanilla sort returns " [
[12,"11","AAB"],
[12,"12","AAA"],
[18,"80","DDD"],
[28,"08","BBB"],
[58,"120","CCC"]
]
if col 0 then returns "[
[12,'12',"AAA"],
[12,'11', 'AAB'],
[18,'80',"DDD"],
[28,'08',"BBB"],
[58,'120',"CCC"]
]"
if col 1 then returns "[
[28,'08',"BBB"],
[12,'11', 'AAB'],
[12,'12',"AAA"],
[18,'80',"DDD"],
[58,'120',"CCC"],
]"
if col 2 then returns "[
[12,'12',"AAA"],
[12,'11', 'AAB'],
[28,'08',"BBB"],
[58,'120',"CCC"],
[18,'80',"DDD"],
]"
*/
}
Solution vary depend on column value is numeric or string.
To sort by first column if value is numeric,
array.sort( (a, b) => a[0] - b[0]);
To sort by second column if value is numeric,
array.sort( (a, b) => a[1] - b[1]);
To sort by first column if value is string/letter,
array.sort( function(a, b) {
const nameA = a[0].toUpperCase(); // to avoid case while sort
const nameB = b[0].toUpperCase();
if(nameA > nameB)
return 1;
else if(nameB > nameA)
return -1;
else
return 0;
})
As my usecase involves dozens of columns, I expanded @jahroy's answer a bit. (also just realized @charles-clayton had the same idea.)
I pass the parameter I want to sort by, and the sort function is redefined with the desired index for the comparison to take place on.
var ID_COLUMN=0
var URL_COLUMN=1
findings.sort(compareByColumnIndex(URL_COLUMN))
function compareByColumnIndex(index) {
return function(a,b){
if (a[index] === b[index]) {
return 0;
}
else {
return (a[index] < b[index]) ? -1 : 1;
}
}
}
Good idea Sabbir Ahmed, but only order by the first character, for three:
array.sort((a, b) => (a[n].charCodeAt(0)*1000000 + a[n].charCodeAt(1)*1000 + a[n].charCodeAt(2)) - (b[n].charCodeAt(0)*1000000 + b[n].charCodeAt(1)*1000 + b[n].charCodeAt(2)));
Sorting two dimensional array specifying the sort order and column. Default order 0 means no change hence order must be specified: 1 => Ascending, -1 => descending. Default column is 0.
let sort2d = (arr2d = [], order = 0, column = 0) => {
if (column < 0 || column > 1) {
if (order == 1)
return arr2d.sort((a, b) => a[column] - b[column])
if (order == -1)
return arr2d.sort((a, b) => b[column] - a[column])
}
return arr2d
}
let arr2d = [ [5, 3], [2, 5], [9, 1], [4, 1] ]
console.log(sort2d(arr2d, 1, -1)) // [ [ 2, 5 ], [ 5, 3 ], [ 9, 1 ], [ 4, 1 ] ]
If you want a solution to sort multi-dimensional integer array where sub-array have a fixed length [ [ -6, 1, 5 ], [ -8, 3, 5 ], [ -8, 2, 6 ], [ -8, 3, 6 ] ]
const array = [ [ -6, 1, 5 ], [ -8, 3, 5 ], [ -8, 2, 6 ], [ -8, 3, 6 ] ]
const multiArraySort = (array, num) => {
return array = array.sort((a,b) => {
let boolean = true
let i = 0
while(boolean){
if(a[i] === b[i]){
if(a[i+1] === b[i+1]){
i < num - 1 ? i++ : boolean = false
}else {
return a[i+1] - b[i+1]
}
} else {
return a[i] - b[i]
}
}
return 0
})
}
// 3 represents the fixed length of sub-array
let sarray = multiArraySort(array, 3) //cant' assign in const array
Answer: [ [ -8, 2, 6 ], [ -8, 3, 5 ], [ -8, 3, 6 ], [ -6, 1, 5 ] ]
The toSorted() method allows us to sort an array. Returns a new array with the ordered elements and does not modify the original. Just like the classic sort() method, we can pass it a comparison function to sort the elements.
const arr = [
[12, "AAA"],
[58, "BBB"],
[28, "CCC"],
[18, "DDD"]
];
let arr1 = arr.toSorted();
let arr2 = arr.toSorted((a, b) => a[0] - b[0]);
let arr3 = arr.toSorted((a, b) => a[1] - b[1]);
console.log(arr1);
console.log(arr2);
console.log(arr3);I recently wrote a database program where CSV files are read in and parsed to arrays of arrays (or a 2 dimensional array if you will). The program runs SQL commands on the data, so I had to write a function for sorting by ascending or descending and also by numeric or string. Certainly the function could be more terse, but I prefer to be as clear as possible.
Note that I make a hard copy of the original data, and return a new array. The new array can then be assigned to the original array if you'd like. I prefer this over in place sorting, but that is a matter of preference.
function orderData(arrays, colIndex, dataType = "STRING", direction = "ASC") {
let newArrays = JSON.parse(JSON.stringify(arrays));//make hard copy
newArrays.sort(sortFunction);//in place sorting
function sortFunction(a, b) {//the sort function
if (dataType === "STRING") {
if (a[colIndex].toString() < b[colIndex].toString()) {
return -1;
}
if (a[colIndex].toString() > b[colIndex].toString()) {
return 1;
}
return 0;
}
else {
if (Number(a[colIndex]) < Number(b[colIndex])) {
return -1;
}
if (Number(a[colIndex]) > Number(b[colIndex])) {
return 1;
}
return 0;
}
}
if (direction === "DESC") {//reverse if called for
newArrays.reverse();
}
return newArrays;
}
Here is an example of it in use:
let array = [[12, "AAA"], [58, "BBB"], [28, "CCC"], [18, "DDD"]];
console.log(array);
console.log();
console.log(orderData(array, 0, "NUMBER", "ASC"));
console.log(orderData(array, 0, "NUMBER", "DESC"));
console.log(orderData(array, 1, "STRING", "ASC"));
console.log(orderData(array, 1, "STRING", "DESC"));
And here are the results:
[ [ 12, 'AAA' ], [ 58, 'BBB' ], [ 28, 'CCC' ], [ 18, 'DDD' ] ]
[ [ 12, 'AAA' ], [ 18, 'DDD' ], [ 28, 'CCC' ], [ 58, 'BBB' ] ]
[ [ 58, 'BBB' ], [ 28, 'CCC' ], [ 18, 'DDD' ], [ 12, 'AAA' ] ]
[ [ 12, 'AAA' ], [ 58, 'BBB' ], [ 28, 'CCC' ], [ 18, 'DDD' ] ]
[ [ 18, 'DDD' ], [ 28, 'CCC' ], [ 58, 'BBB' ], [ 12, 'AAA' ] ]
