fixed frequency data sets are sometimes stored with timespan information spread across multiple columns for examplein this macroeconomic data setthe year and quarter are in different columnsin [ ]data pd read_csv('ch /macrodata csv'in [ ]data year out[ ] nameyearlength in [ ]data quarter out[ ] namequarterlength by passing these arrays to periodindex with frequencythey can be combined to form an index for the dataframein [ ]index pd periodindex(year=data yearquarter=data quarterfreq=' -dec'in [ ]index out[ ]freqq-dec [ length in [ ]data index index in [ ]data infl out[ ] - freqq-decnameinfllength resampling and frequency conversion resampling refers to the process of converting time series from one frequency to another aggregating higher frequency data to lower frequency is called downsamplingwhile converting lower frequency to higher frequency is called upsampling not time series www it-ebooks info