How to transform raw data to fixed-frequency time series? For example I have the following raw data in DataFrame A B 2017-01-01 00:01:01 0 100 2017-01-01 00:01:10 1 200 2017-01-01 00:01:16 2 300 2017-01-01 00:02:35 3 100 2017-01-01 00:02:40 4 100 I'd like to transform it into a time series: 1. 1 minute frequency 1. column A should have sum of values in time interval 1. column B should have mean of values in time interval 1. possibly other functions over other columns Note: Raw data is not periodic. Transformed data should be: A B 2017-01-01 00:01:00 3 200 2017-01-01 00:02:00 7 100