Daiyue Weng wrote: > Hi, I tried to use DataFrame.values to convert a list of columns in a > dataframe to a numpy ndarray/matrix, > > matrix = df.values[:, list_of_cols] > > but got an error, > > IndexError: only integers, slices (:), ellipsis (...), numpy.newaxis > (None) and integer or boolean arrays are valid indices > > so what's the problem with the list of columns I passed in? > > many thanks
Your suggestively named list_of_cols is probably not a list. Have your script print its value and type before the failing operation: print(type(list_of_cols), list_of_cols) > matrix = df.values[:, list_of_cols] -- https://mail.python.org/mailman/listinfo/python-list