Hi Peter,
One way is to process the strings before converting them to dates:
x2<-c("45-12-03","01-06-24","04-9-15","1901-03-04")
add_century<-function(x,changeover=68,previous=19,current=20) {
centuries<-sapply(sapply(x,strsplit,"-"),"[",1)
shortyears<-which(!(nchar(centuries)>2))
century<-rep("",length(x))
century[shortyears]<-ifelse(centuries[shortyears]>changeover,previous,current)
newx<-paste0(century,x)
return(newx)
}
add_century(x2,1)
Jim
On Fri, Apr 17, 2020 at 12:34 AM Peter Nelson via R-help
<r-help@r-project.org> wrote:
>
> I have a data set (.csv) with date (eg date of birth) information stored as
> character vectors that I’m attempting to transform to POSIXct objects using
> the package lubridate (1.7.4). The problem that I’m trying to address is that
> my two digit years are invariably (?) parsed to 20xx. For example,
>
> x <- c("45-12-03","01-06-24","64-9-15”)
> ymd(x)
> [1] "2045-12-03" "2001-06-24" "2064-09-15”
>
> These should be parsed as “1945-12-03” “2001-06-24” “1964-09-15”.
>
> I've tried to use parse_date_time()—based on the documentation it looks to me
> as though the argument cutoff_2000 should allow me to address this, but it’s
> unclear to me how to implement this. As an example, I’ve tried
>
> parse_date_time(x, cutoff_2000 = 01)
>
> but get the following error message (and similar for other similar attempts,
> including cutoff_2000 = 01L)
>
> Error in parse_date_time(x, cutoff_2000 = 1) :
> unused argument (cutoff_2000 = 1)
>
> Thanks for your help!
>
> Peter Nelson, PhD
> Institute of Marine Sciences
> University of California, Santa Cruz
> Center for Ocean Health, Long Marine Lab
> 115 McAllistair Way
> Santa Cruz, CA, 95076, USA
> 707-267-5896
>
>
>
>
>
>
> [[alternative HTML version deleted]]
>
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