How can one ensure that PHP can read all possible international characters when importing data from an Excel file?

To ensure that PHP can read all possible international characters when importing data from an Excel file, you should set the appropriate character encoding for reading the file. This can be achieved by using the PHPExcel library and specifying the UTF-8 encoding when loading the Excel file. Additionally, make sure that the PHP script itself is also set to use UTF-8 encoding to properly handle the international characters.

// Include the PHPExcel library
require 'PHPExcel/PHPExcel.php';

// Set encoding for PHP script
mb_internal_encoding("UTF-8");

// Load the Excel file and specify UTF-8 encoding
$inputFileType = PHPExcel_IOFactory::identify('example.xlsx');
$objReader = PHPExcel_IOFactory::createReader($inputFileType);
$objReader->setReadDataOnly(true);
$objReader->setInputEncoding('UTF-8');
$objPHPExcel = $objReader->load('example.xlsx');

// Process the imported data
// ...