List of variables to split must not specify any variable more than once. When splitting multiple variables, to specify new variable names, provide a cell array with each cell containing the new variable names corresponding to the columns of one of the variables being split. Using a vartype subscripter to specify the variables to split is not supported. Use a character vector, string array, cell array of character vectors, or numeric or logical indices. Specify 'NewVariableNames' as Constant.