[R] If-then with Dates in Date Ranges

[MacQueen, Don]

On possible way, if I understand the question correctly, is to use the
findInterval() function.
Otherwise, solutions depend on details you haven't included.

Here's an example from ?findInterval

  x <- 2:18
  v <- c(5, 10, 15) # create two bins [5,10) and [10,15)
  cbind(x, findInterval(x, v))
 
The cut() function might also work.

Based on the example from ?findInterval, try this:

>  bnds <- Sys.Date() + seq(0,15,5)
>  vals  <- Sys.Date() + 1:15
 
> cbind(vals, findInterval(vals,bnds))
       vals  
 [1,] 15967 1
 [2,] 15968 1
 [3,] 15969 1
 [4,] 15970 1
 [5,] 15971 2
 [6,] 15972 2
 [7,] 15973 2
 [8,] 15974 2
 [9,] 15975 2
[10,] 15976 3
[11,] 15977 3
[12,] 15978 3
[13,] 15979 3
[14,] 15980 3
[15,] 15981 4

> tmp <-  findInterval(vals,bnds)


> cbind(format(vals),tmp)                    tmp
 [1,] "2013-09-19" "1"
 [2,] "2013-09-20" "1"
 [3,] "2013-09-21" "1"
 [4,] "2013-09-22" "1"
 [5,] "2013-09-23" "2"
 [6,] "2013-09-24" "2"
 [7,] "2013-09-25" "2"
 [8,] "2013-09-26" "2"
 [9,] "2013-09-27" "2"
[10,] "2013-09-28" "3"
[11,] "2013-09-29" "3"
[12,] "2013-09-30" "3"
[13,] "2013-10-01" "3"
[14,] "2013-10-02" "3"
[15,] "2013-10-03" "4"



For your one-line fragment, the basic syntax would be

  if (StartDate >= Beg1Date & EndDate <= Beg1Date) inperiod <- 1 else
inperiod <- 0

but of course that handles only one time interval (bin).
A huge if, else if, else if, ... thing could be used, but R has a better
way!



-Don
 

-- 
Don MacQueen

Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062





On 9/17/13 10:52 AM, "Zd Gibbs" <zd.gibbs at yahoo.com> wrote:

>Hello everyone.
>
>I am very much a beginner with R and I am trying to turn the following
>if-then statement into R code. More detail. I want to create a new
>variable: "inperiod" that will be a numeric code. So if a specific event
>start date (StartDate) is greater or equal to a testing date (Beg1Date)
>AND the event end date (EndDate) is less than or equal to the testing
>date (Beg1Date), I want the inperiod code to be 1. I will do this for a
>range of dates so that the code can be anywhere from 1-25.
>
>If StartDate >= Beg1Date & EndDate <= Beg1Date inperiod = 1.
>
>Thanks for any help.
>
>Zeda
>	[[alternative HTML version deleted]]
>