dataframe values.tolist() datatype

Question

I have a dataframe like this:

This dataframe has several columns. Two are of type float: price and change, while

Answer 1

You can convert column-by-column:

by_column = [df[x].values.tolist() for x in df.columns]

This will preserve the data type of each column.

Than convert to the structure you want:

list(list(x) for x in zip(*by_column))

You can do it in one line:

list(list(x) for x in zip(*(df[x].values.tolist() for x in df.columns)))

You can check what datatypes your columns have with:

df.info()

Very likely your column amount is of type float. Do you have any NaN in this column? These are always of type float and would make the whole column float.

You can cast to int with:

df.values.astype(int).tolist()