Working with files often starts off simple. open the file, read, and process. That approach works perfectly well, until the file happens to be an Excel file.
A Common Assumption
At first, an Excel file (.xlsx) looks like just another data file, rows, columns and values. nothing unusual. So it's natural to assume it can be read the same way as a .txt ot .csv file. But that's where things start to break.
Why Excel files behave differently
The key difference is how the data is stored:
-> .txt / .csv - plain text, line-by-line.
-> .

