Convert array of strings to array of numbers?

Question

I am trying to convert an array of numbers (represented as strings) to an array of numbers.

Here is an example array: [ '39.4K', '83.4K', '1.5M', '111.3K', '5878' ]; the numbers may have the conventional "K" and "M" suffixes, denoting factors of 1000 and 1000000, respectively. The desired output of the previous example is [39400, 83400, 1500000, 111300, 5878].

Here is what I have so far:

var sample = [ '39.4K', '83.4K', '1.5M', '111.3K', '5878' ]

function convert(arr) {
    var conversions = {'K':1000, 'M':1000000}
    var result = []
    for (entry of arr) {
        var sep = entry.split(/(?=[A-Z])/)
        if (sep.length == 1) {
            result.push(parseFloat(sep[0]))
        } else {
            var number = parseFloat(sep[0]) * conversions[sep[1]]
            result.push(number)
        }
    }
    return result
}

console.log(convert(sample))

I think this works, but are there any ways to improve my code? I would have assumed JS has something to automatically convert different representations of numbers. Any advice or suggestions (using only vanilla JS) greatly appreciated.

What you've got is fine, there are no built-in functions to do anything better. — Pointy, Jun 25 '22 at 18:07
https://stackoverflow.com/questions/4437916/how-to-convert-all-elements-in-an-array-to-integer-in-javascript — dippas, Jun 25 '22 at 18:14

score 3 · Accepted Answer · answered Jun 25 '22 at 18:11

When turning one array into another by transforming each element, .map is the appropriate approach. Rather than parseFloat(sep[0]), consider destructuring the split result and conditionally multiplying with the conversions value for a more concise approach.

const sample = [ '39.4K', '83.4K', '1.5M', '111.3K', '5878' ]
const conversions = {'K': 1e3, 'M': 1e6};

const convert = arr => arr.map((str) => {
  const [numPart, suffix] = str.split(/(?=[A-Z])/);
  return numPart * (suffix ? conversions[suffix] : 1);
});

console.log(convert(sample))

score 1 · Answer 2 · answered Jun 25 '22 at 18:11

You could map the results and take the unit from object or one after splitting.

function convert(array) {
    const conversions = { K: 1000, M: 1000000 };
    return array.map(s => {
        const [v, u] = s.split(/(?=[KM]$)/);
        return v * (conversions[u] || 1);
    });
}

console.log(convert(['39.4K', '83.4K', '1.5M', '111.3K', '5878']))

Convert array of strings to array of numbers?

2 Answers2