CSV file reading and writing in PHP - Mini Project: Build & Apply

CSV file reading and writing

📖 Scenario: You work in a small shop and want to keep track of your products and prices using a CSV file. You will read the CSV file, update prices, and save the changes back to the file.

🎯 Goal: Build a PHP script that reads a CSV file named products.csv, updates the prices by increasing them by 10%, and writes the updated data back to the same CSV file.

📋 What You'll Learn

Read data from a CSV file named products.csv

Store the CSV data in an array

Increase each product's price by 10%

Write the updated data back to products.csv

Use PHP built-in functions for CSV handling

💡 Why This Matters

🌍 Real World

Small shops or simple apps often use CSV files to store product lists and prices because CSV files are easy to read and edit.

💼 Career

Knowing how to read and write CSV files is useful for data import/export tasks, report generation, and simple database alternatives in PHP development.

1

Create the initial CSV file

Create a CSV file named products.csv with these exact lines:
Apple,1.00
Banana,0.50
Cherry,2.00

PHP

# Create the file products.csv with the given lines

Need a hint?

Use file_put_contents to create and write to the CSV file.

2

Read the CSV file into an array

Read the CSV file products.csv line by line using fopen and fgetcsv, and store each row as an array inside a variable called products.

PHP

<?php
file_put_contents('products.csv', "Apple,1.00\nBanana,0.50\nCherry,2.00\n");

// Read the CSV file into the products array
# Your code here

Need a hint?

Use fopen to open the file and fgetcsv inside a while loop to read each row.

3

Increase each product price by 10%

Use a foreach loop with variables index and product to iterate over products. Increase the price (second element) by 10% and update products[index][1] with the new price formatted to 2 decimal places.

PHP

<?php
file_put_contents('products.csv', "Apple,1.00\nBanana,0.50\nCherry,2.00\n");

$products = [];
if (($handle = fopen('products.csv', 'r')) !== false) {
    while (($data = fgetcsv($handle)) !== false) {
        $products[] = $data;
    }
    fclose($handle);
}

// Increase prices by 10%
# Your code here

Need a hint?

Convert the price to float, multiply by 1.10, then format back to string with 2 decimals.

4

Write the updated data back to the CSV file

Open products.csv for writing using fopen with mode 'w'. Use a foreach loop to write each product array to the file using fputcsv. Close the file with fclose. Then print "Updated CSV saved." to confirm.

PHP

 $product) {
    $price = (float)$product[1];
    $new_price = $price * 1.10;
    $products[$index][1] = number_format($new_price, 2, '.', '');
}

// Write updated products back to products.csv and print confirmation
# Your code here

Need a hint?

Use fopen with 'w' mode, fputcsv inside a loop, then fclose. Finally, print the confirmation message.