Mixed types columns processing improvement
Created by: Dreamlone
A modification was made to improve the logic of processing tables with mixed types columns.
Now if the column contains the string values '?', 'x', '1', '2', '3', '4', the following processing is done. The algorithm tries to convert the column into float type. If the column contains cells that cannot be converted into float and the ratio of such cells exceeds 50% and at the same time there are cells that can be converted, such column is removed from the table.