.nightly_daily_cf: Period custom function
Description
nightly period custom function, to use with nightly_metrics
Usage
.nightly_daily_cf(timestamp, night_data, int_start)
Value
a vector of the same length as TIMESTAMP with the collapsed values.
Arguments
- timestamp
TIMESTAMP
- night_data
as it comes inside of sfn_metrics
- int_start
interval start as supplied to sfn_metrics
Details
This function will be supplied as "period" argument to summarise_by_period
when daily nightly metrics are requested.