Converting Pandas Dataframe types
df = df.convert_objects(convert_numeric=True) will work in most cases.
I should note that this copies the data.  It would be preferable to get it to a numeric type on the initial read.  If you post your code and a small example, someone might be able to help you with that.
I have a pandas dataFrame created through a mysql call which returns the data as object type.
The data is mostly numeric, with some 'na' values.
How can I cast the type of the dataFrame so the numeric values are appropriately typed (floats) and the 'na' values are represented as numpy NaN values?