What are the potential pitfalls of opening CSV files directly in Excel instead of importing them?

Opening CSV files directly in Excel can lead to data formatting issues, such as incorrect date formats, loss of leading zeros in numbers, and misinterpretation of special characters. To avoid these problems, it is recommended to import CSV files into Excel using the data import feature, which allows you to specify the correct data types for each column.

// Import CSV file into Excel using PHPExcel library
$objPHPExcel = PHPExcel_IOFactory::load('file.csv');