As far as I can tell, the following MRE conforms to the relevant documentation: import polars df = polars.read_excel( "/Volumes/Spare/foo.xlsx", engine="calamine", sheet_name="natsav", read_options={"header_row": 2}, columns=(1,2,4,5,6,7), # columns 0 and 3 are not needed ) print(df.head()) The issue here is that the documentation states that for the columns parameter: Columns to read from the sheet; if not specified, all columns are read. Can be given as a sequence of column names or indices. Clearly, a tuple is a sequence. However, running this code results in an exception as follows: _fastexcel.InvalidParametersError: invalid parameters: `use_columns` callable could not be called (TypeError: 'tuple' object is not callable) Further research reveals that the required callable should return bool. So: def colspec(c): print(type(c)) return True I then change the read_excel call to include columns=colspec. The program now runs without exception and reveals that the parameter passed is a class of type builtins.ColumnInfoNoDtype. Unfortunately, I can't find any documentation for that type. Is the documentation wrong? How is one supposed to used polars.read_excel to load only certain specific columns? Continue reading...
