character vector specifying all columns that should be
part of the key. Defaults to the dim.order specified by swissdata.
filter
function A function that is applied to the raw data.data table after it is read. Useful for
filtering out undesired data.
aggregates
list A list of dimensions over which to aggregate data. The names of this list determing
which function is used to calculate the aggregate (e.g. sum, mean etc.). Defaults to sum.
keep_last_freq_only
in case there is a frequency change in a time series,
should only the part of the series be returned that has the same frequency as
the last observation. This is useful when data start out crappy and then stabilize
Details
The order of dimensions in key_columns determines their order in the key
The resulting ts_key will be of the form <swissdata-set-name>.<instance of key_columns[1]>...