Question 232259 in Javascript Question posted in
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Transform multi-dimensional JavaScript array

I have the following javascript (typescript) array:

[[1262304000000,0.7537], [1262563200000,0.6951], [1262649600000,0.6925]]

How can I transform it to the following using map operator? (Basically second element of the array has been converted to % value. E.g. 0.7537 to 75.37. However, I am not sure how to access the second element of the array)

[[1262304000000,75.37], [1262563200000,69.51], [1262649600000,69.25]]
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2

Answers


  1. 0 
    const data = [[1262304000000, 0.7537], [1262563200000, 0.6951], [1262649600000, 0.6925]];

const convertedData = data.map(item => {
  const timestamp = item[0];
  const percent = item[1] * 100; // Convert the second item to a percentage
  return [timestamp, percent]; // return both items
});

console.log(convertedData);
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  2. 0

    Each element of your array is itself an array, and therefore you can access its elements via numeric indices like v[0] for the first element and v[1] for the second:

    const a = [[1262304000000,0.7537], [1262563200000,0.6951], [1262649600000,0.6925]];
console.log(a.map(v => [v[0], v[1] * 100]));
// [[1262304000000, 75.37], [1262563200000, 69.51], [1262649600000, 69.25]]

    But it’s also easy to use destructuring assignment to copy each element’s members into individual named parameters before using them:

    const a = [[1262304000000,0.7537], [1262563200000,0.6951], [1262649600000,0.6925]];
console.log(a.map(([x, y]) => [x, y*100]));
// [[1262304000000, 75.37], [1262563200000, 69.51], [1262649600000, 69.25]]

    Playground link to code

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