indicateing to which interval a date belongs

Question

4/1/2014 0:11   40.769  -73.9549    B02512|
4/1/2014 0:17   40.7267 -74.0345    B02512|
4/1/2014 0:21   40.7316 -73.9873    B02512|
4/1/2014 0:28   40.7588 -73.9776    B         


        

Answer 1

Using lubridate's floor_date function:

df$interv<-lubridate::floor_date(df$time, unit="15 minutes")

(This assumes that your time column is some recognized date-time format (e.g., POSIXt), which it doesn't seem to be from your sample's formatting.)

For example:

a<-Sys.time()
a
[1] "2019-01-08 09:22:22 EST"
floor_date(a,unit="15 minutes")
[1] "2019-01-08 09:15:00 EST"