What is CSV?

CSV (Comma-Separated Values) is a simple file format used to store and exchange tabular data. It is widely used in data analysis, spreadsheets, databases, and data exchange between applications.

1. Why Use CSV?

Lightweight: Simple text-based format.
Widely Supported: Works with Excel, Google Sheets, Python, databases, etc.
Easy to Read and Write: No complex formatting.
Portable: Can be used across different systems and applications.

2. CSV File Structure

Each line in a CSV file represents a row, and values are separated by commas.

Name, Age, Email
John Doe, 30, johndoe@example.com
Alice Smith, 25, alicesmith@example.com

3. CSV Delimiters

Other delimiters like semicolons or tabs can be used:

Semicolon (`;`)

Name; Age; Email
John Doe; 30; johndoe@example.com

Tab-separated (`\t`)

Name    Age    Email
John Doe    30    johndoe@example.com

4. Working with CSV Files

In Python

Reading a CSV File

import csv

with open("data.csv", "r") as file:
    reader = csv.reader(file)
    for row in reader:
        print(row)

Writing to a CSV File

import csv

data = [
    ["Name", "Age", "Email"],
    ["John Doe", 30, "johndoe@example.com"],
    ["Alice Smith", 25, "alicesmith@example.com"]
]

with open("output.csv", "w", newline="") as file:
    writer = csv.writer(file)
    writer.writerows(data)

In JavaScript

Parsing CSV Data

let csvText = "Name,Age,Email\nJohn Doe,30,johndoe@example.com";
let rows = csvText.split("\n").map(row => row.split(","));
console.log(rows);

5. CSV vs Other Formats

Feature	CSV	JSON	XML
Readability	Simple, human-readable	Readable, but structured	Verbose, hierarchical
Structure	Flat (rows/columns)	Key-value pairs	Tree-based

6. Handling Special Cases

1. Handling Commas in Values

Values containing commas must be enclosed in quotes (`"`).

Name, Age, Address
"John Doe", 30, "123 Main St, New York"

2. Handling New Lines in Values

Use quotes around values that contain line breaks.

Name, Description
"Product 1", "This is a great product.
It has multiple features."

3. Handling Missing Data

Use empty fields for missing values.

Name, Age, Email
John Doe, 30, johndoe@example.com
Alice Smith, , alicesmith@example.com

7. Where is CSV Used?

Data Import/Export (Databases, Excel, Google Sheets).
Web Applications (Uploading and downloading data).
APIs (Returning structured tabular data).
Data Science & Machine Learning (Storing large datasets).

Conclusion

CSV is a simple and effective format for storing tabular data. It is widely supported across applications and is easy to process programmatically.