Obtain a package 1st version's date of publication

Question

Documentation of R packages only include the date of last update/publication. Numbering of versions do not follow a common pattern to all packages. Therefore, it is quite difficult to know at a glance if the package is old or new. Sometimes you need to decide between two packages with similar functions and knowing the age of a package could guide the decision.

My first approach was to plot downloads per year: By traking CRAN downloads. This methods provides also the relative popularity/usage of a package. However, this requires a lot of memory and time to proceed. Therefore, I would rather have a faster way to look into the history of one package.

Is there a quick way to know or vizualize the first version's date of release of one specific package or even to compare several pakages at once?

The purpose is to facilitate a mental mapping of all available packages in R, especially for newcomers. Getting to know packages and managing them is probably the main challenge why people give up on R.

Answer 1

Just for fun:

## not all repositories have the same archive structure!
archinfo <- function(pkgname,repos="http://www.cran.r-project.org") {
    pkg.url <- paste(contrib.url(repos),"Archive",pkgname,sep="/")
    r <- readLines(pkg.url)
    ## lame scraping code
    r2 <- gsub("<[^>]+>"," ",r)   ## drop HTML tags
    r2 <- r2[-(1:grep("Parent Directory",r2))]  ## drop header
    r2 <- r2[grep(pkgname,r2)]                  ## drop footer
    strip.white <- function(x) gsub("(^ +|  +$)","",x)
    r2 <- strip.white(gsub("&nbsp;","",r2))     ## more cleaning
    r3 <- do.call(rbind,strsplit(r2," +"))      ## pull out data frame
    data.frame(
        pkgvec=gsub(paste0("(",pkgname,"_|\\.tar\\.gz)"),"",r3[,1]),
        pkgdate=as.Date(r3[,2],format="%d-%b-%Y"),
        ## assumes English locale for month abbreviations
        size=r3[,4])
}
AERinfo <- archinfo("AER")
lme4info <- archinfo("lme4")
comb <- rbind(data.frame(pkg="AER",AERinfo),
              data.frame(pkg="lme4",lme4info))

We can't compare package numbers directly because everyone uses different numbering schemes ...

library(dplyr) ## overkill
comb2 <- comb %>% group_by(pkg) %>% mutate(numver=seq(n()))

If you want to arrange by package date:

comb2 <- arrange(comb2,pkg,pkgdate)

Pretty pictures ...

library(ggplot2); theme_set(theme_bw())
ggplot(comb2,aes(x=pkgdate,y=numver,colour=pkg))+geom_line()