This function takes a dataframe of heat waves, as created by
gen_hw_set, and calculates the total number of extreme event days in
the dataframe (sum of the number of days in each event for all events
in the dataset).
Usage
heatwave_days(hw_datafr)
Arguments
hw_datafr
A dataframe of extreme events and their characteristics, as
created by gen_hw_set
Value
A numeric value with the number of extreme event days in a dataframe
of heat waves, as generated by gen_hw_set.