How to use intersect() function with date ranges in R

Question

Here is my code:

a<-"2015-12-13 09:00:00"           
b<-"2015-12-13 12:00:00"
c<-interval(a,b)

d<-"2015-12-13 09:00:00"           
e<-"2015-12-13 12:00:00"
f<-interval(d,e)
h<-intersect(c,f)
h

The values of c,f and h are:

> h
[1] 10800
> c
[1] 2015-12-13 09:00:00 UTC--2015-12-13 12:00:00 UTC
> f
[1] 2015-12-13 09:00:00 UTC--2015-12-13 12:00:00 UTC
> 

But, when I give a different date/time range. The intersect function does not work. For example: If I change the time of the variable d and e from 09:00:00-12:00:00 to 09:00:00 - 10:00:00, I am expecting the intersect function to give me the minutes for 1 hour that is common.

a<-"2015-12-13 09:00:00"           
b<-"2015-12-13 12:00:00"
c<-interval(a,b)

d<-"2015-12-13 09:00:00"           
e<-"2015-12-13 10:00:00"
f<-interval(d,e)
h<-intersect(c,f)
h

Output:

numeric(0)
> c
[1] 2015-12-13 09:00:00 UTC--2015-12-13 12:00:00 UTC
> f
[1] 2015-12-13 09:00:00 UTC--2015-12-13 10:00:00 UTC

I get numeric(0). Can someone please help me with this.

Answer 1

For the sake of avoiding answering in the comments:

As J_F mentions above, you need to use the intersect function from lubridate. In case you face problems because you need intersect from both lubridate and dplyr you can use the double colon ::.

Double colon :: is used to specify from which package you call a function and overcomes masking. So in your code:

a<-"2015-12-13 09:00:00"           
b<-"2015-12-13 12:00:00"
c<-interval(a,b)

d<-"2015-12-13 09:00:00"           
e<-"2015-12-13 10:00:00"
f<-interval(d,e)
h<-lubridate::intersect(c,f)
h

[1] 2015-12-13 09:00:00 UTC--2015-12-13 10:00:00 UTC