Is there some simple way in PyQt to store data from QTableWidget to some file, and use that content again? It's not a critical task for me, so i don't want to invent some custom xml rules or somethin else.
Qt provides a (modified) Model->View framework and so the data in a table, or any other GUI widget, is stored in a data model. It's the data in the model that you want to persist. The GUI widgets themselves don't provide any facilities to do this.
There's no standard data persistence method implemented in the Qt data model components. Qt does provide fatures to persist data structures to disc in binary (QDataStream), text (QTextStream) and XML (QDomDocument) formats. However if you're using PyQt you're probably better off using Python's built-in data persistence libraries such as Pickle or Shelve, or it's JSON or XML libraries.
How to import/export QTableWidget to some file?