ValueError: could not convert string to float: 'BENIGN'

This error message is typically seen when attempting to convert a string that does not represent a numerical value into a float data type. In this specific case, the error message suggests that the string 'BENIGN' cannot be converted into a float.

It is possible that the code is attempting to convert a column or variable that contains a mixture of numerical and non-numerical values into a float data type. One possible solution is to remove the non-numerical values from the column or variable before attempting to convert it to a float.

Alternatively, if the 'BENIGN' value is actually a valid value in the data set, it may be necessary to use a different data type or handle it separately from the numerical values in the column or variable.