Working with CSV in PHP: PhpSpreadsheet Library

What is PhpSpreadsheet and why is it needed?

PhpSpreadsheet is a powerful PHP library for working with spreadsheets. It allows you to read, write, and edit files in CSV, XLS, XLSX, ODS, and other formats. Unlike built-in PHP functions (e.g., fgetcsv), PhpSpreadsheet offers an object-oriented approach, automatic encoding handling, support for styles, formulas, and large data volumes. The library is ideal for importing/exporting data from web forms, generating reports, migrating between databases, and integrating with Excel/Google Sheets.

Installation

Installation is done via Composer:

composer require phpoffice/phpspreadsheet

After installation, include the autoloader:

require 'vendor/autoload.php';

Main Features

• Reading CSV — loading a file into a Spreadsheet object with automatic delimiter detection.
• Writing CSV — creating and saving a file with configurable delimiter, enclosure, and BOM.
• Working with sheets — creating, deleting, renaming, and copying sheets.
• Formatting — cell styles (fonts, colors, borders, alignment).
• Formulas and functions — support for SUM, AVERAGE, IF, and others.
• Handling large data — streaming writing via Xlsx Writer to reduce memory consumption.

Code example: reading and writing CSV

Reading a CSV file and outputting data:

use PhpOffice\\PhpSpreadsheet\\IOFactory;

$inputFileName = './data.csv';$spreadsheet = IOFactory::load($inputFileName);$worksheet = $spreadsheet->getActiveSheet();$data = $worksheet->toArray();

foreach ($data as $row) {    echo implode(', ', $row) . "";}

Writing data to CSV:

use PhpOffice\\PhpSpreadsheet\\Spreadsheet;use PhpOffice\\PhpSpreadsheet\\Writer\\Csv;

$spreadsheet = new Spreadsheet();$sheet = $spreadsheet->getActiveSheet();

$sheet->setCellValue('A1', 'Name');$sheet->setCellValue('B1', 'Email');$sheet->setCellValue('A2', 'Ivan');$sheet->setCellValue('B2', 'ivan@example.com');

$writer = new Csv($spreadsheet);$writer->setDelimiter(';');$writer->setEnclosure('"');$writer->save('./output.csv');

When to use

PhpSpreadsheet is recommended in the following cases:

• Support for multiple formats (CSV, XLSX, ODS) in one project is required.
• Precise formatting (colors, fonts, cell merging) is needed.
• You need to work with formulas or large datasets (more than 10,000 rows).
• You prefer an OOP style and do not want to write low-level parsers.

For simple tasks (e.g., reading a single CSV with a known structure), built-in PHP functions may suffice. But if the project grows and requires flexibility, PhpSpreadsheet will become an indispensable tool.