concept cell sheet book definition is data unit is named two dimensional array of data units is dictionary of two dimensional array of data units pyexcel data model python data type sheet book data source data source is storage format of structured data the most popular data source is an excel file libre office/microsoft excel can easily be used to generate an excel file of your desired format besides physical filethis library recognizes three additional types of source excel files in computer memory for examplewhen file is uploaded to python server for information processing if it is relatively smallit can be stored in memory database tables for examplea client would like to have snapshot of some database table in an excel file and asks it to be sent to him python structures for examplea developer may have scraped site and have stored data in python array or dictionary he may want to save this information as file reading from and writing to data source is modelled as parsers and renderers in pyexcel excel data sources and database sources support read and write other data sources may only support read onlyor write only methods here is list of data sourcesdata source array dictionary records excel files excel files in memory excel files on the web django models sql models database querysets textual sources read and write properties read and write same as above same as above same as above same as above read only read and write read and write read only write only data format this library and its plugins support most of the frequently used excel file formats support the project