%in% very slow for Date class since R 4.3

On Thu, 26 Jun 2025, Dirk Eddelbuettel writes:

On 25 June 2025 at 07:11, Kurt Hornik wrote:
| >>>>> hormutz screed writes:
| 
| Thanks.  Makes sense to me, needs some discussion in R Core ...

Nice to see this in NEWS [1]:

  CHANGES IN R-devel BUG FIXES
  
  ?<Date> %in% set? has become as fast again, as it was before R 4.3.0, via
  new S3 method ?mtfrm.Date?. 

Dirk

[1] https://developer.r-project.org/blosxom.cgi/R-devel via the RSS feed

As a remark -- not a complaint ;-) --, in R 4.5.1: 

  match("2025-01-01", as.Date("2025-01-01"))
  ## [1] 1

which is, in a way, consistent with

  "2025-01-01" == as.Date("2025-01-01")
  ## [1] TRUE


In R-devel (2025-06-26 r88362):

  match("2025-01-01", as.Date("2025-01-01"))
  ## [1] NA

  "2025-01-01" == as.Date("2025-01-01")
  ## [1] TRUE

Enrico Schumann
Lucerne, Switzerland
https://enricoschumann.net