function data_map() { var data = [ ['a','b', 1], ['c','d', 2], ['e','f', 3], ['g','h', 4] ] var newData = data.map(function(row){ return [row[0], ro

Function data_map()#

var data = [ 
    ['a','b', 1], 
    ['c','d', 2], 
    ['e','f', 3], 
    ['g','h', 4] 
];

var newData = data.map(function(row){ 
    return [row[0], row[2]]; 
});

The data_map() function creates a new array, newData, by mapping each element from the original array, data. Each element in the data array is itself an array of three elements. The first two elements are strings, and the third element is a number.

The Callback Function#

The callback function used in the map() method takes a single argument, row, which represents the current element from the data array being processed. The function then returns a new array containing only the first and third elements of the current row.

var newData = data.map(function(row){ 
    return [row[0], row[2]]; 
});

Alternative Ways to Achieve the Same Result#

Another way to achieve the same result is by using arrow function syntax instead of function declaration syntax. This would look like:

var newData = data.map((row) => [row[0], row[2]]);

Additionally, one could use destructuring assignment to directly extract the first and third elements of each row into a new array. This would look like:

var newData = data.map(([first, second, third]) => [first, third]);