I'm trying to calculate sums of each columns of csv. I'm able to read a csv in js using readfile method. I also was able to loop through it and parsed data into array of objects. Now I just to figure out a way to add up all the column elements, that's where I'm struggling. My csv object is in array of object format which looks like this.
[
{ item: '18', count: '180' },
{ item: '19', count: '163' },
{ item: '20', count: '175' },
{ item: '', count: undefined }
]
CSV input is like this:
item,count
18,180
19,163
20,175
I want to add 18 + 19 + 20 and final answer should look like this [57,518].
Here's I've done so far, I just need help to make this better and column wise adding logic in JS, please help.
const fs = require('fs')
let result = []
var dataArray = []
fs.readFile(filename, 'utf8', function (err, data) {
dataArray = data.split(/\r?\n/);
// console.log("dataArray", dataArray)
var headers = dataArray[0].split(",");
for (var i = 1; i < dataArray.length; i++) {
var obj = {};
console.log("dataArray", dataArray)
var currentline = dataArray[i].split(",");
for (var j = 0; j < headers.length; j++) {
obj[headers[j]] = currentline[j];
}
result.push(obj);
}
})
You can iterate through each row of your csv and sum up values of items and count using array#reduce and array#forEach.
const fs = require('fs').promises;
const fileName = 'data.csv'
const calculateSum = async () => {
const data = await fs.readFile(fileName, 'utf-8');
const dataArray = data.split(/\r?\n/);
const header = dataArray[0].split(',')
const result = dataArray.slice(1).reduce((sum, arr) => {
arr.split(',').forEach((v, i) => {
sum[i] = (sum[i] || 0) + Number(v.trim());
})
return sum;
}, []);
console.log(result);
}
Generic function
let dataArray = [
{ item: '18', count: '180' },
{ item: '19', count: '163' },
{ item: '20', count: '175' },
{ item: '', count: undefined }
]
const sums = dataArray.reduce((sum, tableRow) => {
Object.keys(tableRow).forEach((obj) => {
if (Number(tableRow[obj])) sum[obj] = (sum[obj] || 0) + Number(tableRow[obj]);
})
return sum;
}, []);
console.log(sums) // [ item: 57, count: 518 ]