pandas resample documentation

Ryan Saxe picture Ryan Saxe · Jun 8, 2013 · Viewed 115.4k times · Source

So I completely understand how to use resample, but the documentation does not do a good job explaining the options.

So most options in the resample function are pretty straight forward except for these two:

  • rule : the offset string or object representing target conversion
  • how : string, method for down- or re-sampling, default to ‘mean’

So from looking at as many examples as I found online I can see for rule you can do 'D' for day, 'xMin' for minutes, 'xL' for milliseconds, but that is all I could find.

for how I have seen the following: 'first', np.max, 'last', 'mean', and 'n1n2n3n4...nx' where nx is the first letter of each column index.

So is there somewhere in the documentation that I am missing that displays every option for pandas.resample's rule and how inputs? If yes, where because I could not find it. If no, what are all the options for them?

Answer

Matti John picture Matti John · Jun 8, 2013
B         business day frequency
C         custom business day frequency (experimental)
D         calendar day frequency
W         weekly frequency
M         month end frequency
SM        semi-month end frequency (15th and end of month)
BM        business month end frequency
CBM       custom business month end frequency
MS        month start frequency
SMS       semi-month start frequency (1st and 15th)
BMS       business month start frequency
CBMS      custom business month start frequency
Q         quarter end frequency
BQ        business quarter endfrequency
QS        quarter start frequency
BQS       business quarter start frequency
A         year end frequency
BA, BY    business year end frequency
AS, YS    year start frequency
BAS, BYS  business year start frequency
BH        business hour frequency
H         hourly frequency
T, min    minutely frequency
S         secondly frequency
L, ms     milliseconds
U, us     microseconds
N         nanoseconds

See the timeseries documentation. It includes a list of offsets (and 'anchored' offsets), and a section about resampling.

Note that there isn't a list of all the different how options, because it can be any NumPy array function and any function that is available via groupby dispatching can be passed to how by name.