It depends on what type of object you're using in pandas as well as whether you ever need to use a User Defined function e.g. pd.Series.map. Crossing between p

It depends on what type of object you're using in pandas as well as whether you ever need to use a User Defined function e.g. pd.Series.map. Crossing between python objects and C objects is incredibly slow, and python defined UDFs will usually run at python speed. In most of my projects I'm unable to avoid using a udf/python data manipulation at some point.