[R] Need help in handling date

[Marc Schwartz]

On Jul 7, 2010, at 7:40 AM, Christofer Bogaso wrote:

> Dear all, I have a date related question. Suppose I have a character string
> "March-2009", how I can convert it to a valid date object like
> as.yearmon("2009-01-03") in the zoo package? Is there any possibility there?
> 
> Ans secondly is there any R function which will give the names of of all
> months as "LETTERS" does?
> 
> Thanks for your time.


You may need to append a default day, so something like:

> as.Date(paste("March-2009", "-15", sep = ""), format = "%B-%Y-%d")
[1] "2009-03-15"

Otherwise on OSX, I get:

> as.Date("March-2009", format = "%B-%Y")
[1] NA

The above behavior regarding missing components is system specific, as per the Note in ?as.Date. Also see ?strptime for the formatting options.

For the second part:

> month.name
 [1] "January"   "February"  "March"     "April"     "May"      
 [6] "June"      "July"      "August"    "September" "October"  
[11] "November"  "December" 

See ?LETTERS

HTH,

Marc Schwartz