Question

How to sort 2D array (matrix) by first column value in Node.js

Answer 1

function compareFirstColumn(a, b) {
    if (a[0] === b[0]) {
        return 0;
    }
    else {
        return (a[0] < b[0]) ? -1 : 1;
    }
}

const matrix = [[41, 'java', 'a'], [15, 'nodejs', 'z'], [3, 'c', 'x'], [20, 'c++', 'q']];

matrix.sort(compareFirstColumn);

console.log(matrix);




/*
run:

[
  [ 3, 'c', 'x' ],
  [ 15, 'nodejs', 'z' ],
  [ 20, 'c++', 'q' ],
  [ 41, 'java', 'a' ]
]

*/

 

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Answer 2

const matrix = [[41, 'java', 'a'], [15, 'nodejs', 'z'], [3, 'c', 'x'], [20, 'c++', 'q']];

matrix.sort(function(a, b) {
    return a[0] - b[0]
});

console.log(matrix);




/*
run:

[
  [ 3, 'c', 'x' ],
  [ 15, 'nodejs', 'z' ],
  [ 20, 'c++', 'q' ],
  [ 41, 'java', 'a' ]
]

*/

 

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