Re: inverting a timeDate sequence Summary of Replies

["Paul H. Lasky" <phlasky@earthlink.net>]

    How do you create a timeDate sequence with the latest date as the first element and oldest date the last element, AND exclude weekends (utilizing Splus 6.1)?  The following efforts were unsuccessful:

 

   td = timeSeq(from="9/15/2003", to = "4/15/2003", by=-"bizdays")

 

   td = timeSeq(from="9/15/2003", to="4/15/2003", by = "bizdays")

 

or

 td1 = timeSeq(from="4/15/2003", to"9/15/2003", by="bizdays")

td = -sort(-td1)  [ sort does not work with timeDate sequences]

 

  Thanks to Jeffrey Wang, Chuck Taylor, Tony Plate, James Holman, and Nick Ellis for helpful replies.  There are 3 ways to easily invert or reverse a timeDate sequence:

 

  The most direct way is simply to :

  1)  td = td1[ length(td1): 1 ], where td is the reversed sequence and td1 the forward sequence. 

 

  2) Nick Ellis pointed out another direct way:

 

    td=timeSeq(from="9/15/2003", to "4/15/2003, by = "bizdays", k.by = -1)

 [ it always helps to read the language reference thoroughly...]

 

 3) Finally you can use the rev function:

   td = rev(td1)

  

 

Paul H. Lasky

B & P Consultants

Rancho Santa Fe, CA