Python pandas convert datetime to timestamp effectively through dt accessor

Question

I have a dataframe with some (hundreds of) million of rows. And I want to convert datetime to timestamp effectively. How can I do it?

My sample df:

Answer 1

If you don't want to use numpy you can use pure pandas conversions

df['ts'] = pd.to_timedelta(df['datetime'], unit='ns').dt.total_seconds().astype(int)