How to read and use a column in a local CSV file with javascript?

Question

I have a CSV file and I need to display in the terminal only the second column. I'm using javascript and nodejs. My CSV file is in a local folder. My CSV data look like this:

name,emails,name1,email1,name2,email2,name3,email3,name4,email4,name5,email5

It's like an array with two columns and six rows, first one with name and second one with emails. I only want to return the list of emails without the heading in the terminal. Later I'll have to use this email list to compare it with an other array.

I think it is possible with papaparse but I don't understand how to use it. I also know that fs module can be use to read the entire file.

If it's possible to convert the data in an array with or without keys/values like this it will also be perfect:

[ name:'name1', email:'email1', name:'name2', email:'email2', name:'name3', email:'email3', name:'name4', email:'email4', name:'name5', email:'email5' ]

Knowing that I also have to do it with an other CSV file that contain 9 columns and 960 rows.

Terry Lennox · Accepted Answer · 2020-10-15 13:41:04Z

1

This code should parse a CSV file in the format you mention, e.g.

test.csv

name,emails
name1,email1
name2,email2
name3,email3
name4,email4
name5,email5

app.js

const Papa = require('papaparse');
const fs = require("fs");

let csvData = fs.readFileSync("test.csv", "utf-8");
csvData = csvData.trim().replace(/([^,]+),\s*([^,]+),\s*/gi, '$1,$2\n');
console.log("Adjusted csv:", csvData);

let { meta, data } = Papa.parse(csvData, { header: true });

console.log("Parsed data:", data);
console.log("Metadata:", meta);

The parsed data would look like so:

[
  { name: 'name1', emails: 'email1' },
  { name: 'name2', emails: 'email2' },
  { name: 'name3', emails: 'email3' },
  { name: 'name4', emails: 'email4' },
  { name: 'name5', emails: 'email5' }
]

edited Oct 15, 2020 at 13:41

answered Oct 15, 2020 at 13:05

Terry Lennox

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10 Comments

Samy Rharade Over a year ago

Not exactly but I think it's because my CSV is strange, it give me something like this:

Samy Rharade Over a year ago

Yes it look exactly like this

Terry Lennox Over a year ago

I've updated the code to split the data into rows so PapaParse can process it.

Samy Rharade Over a year ago

Sorry my bad, i didn't see the other console.log

Samy Rharade Over a year ago

Thank you very much it's exactly what I wanted

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