A simple S3 class for representing numeric versions including package versions, and associated methods.

```
numeric_version(x, strict = TRUE)
package_version(x, strict = TRUE)
R_system_version(x, strict = TRUE)
getRversion()
```

x

a character vector with suitable numeric version strings (see
‘Details’); for `package_version`

, alternatively an R
version object as obtained by `R.version`

.

strict

a logical indicating whether invalid numeric versions should results in an error (default) or not.

Numeric versions are sequences of one or more non-negative integers,
usually (e.g., in package `DESCRIPTION`

files) represented as
character strings with the elements of the sequence concatenated and
separated by single `.` or `-` characters. R package
versions consist of at least two such integers, an R system version
of exactly three (major, minor and patchlevel).

Functions `numeric_version`

, `package_version`

and
`R_system_version`

create a representation from such strings (if
suitable) which allows for coercion and testing, combination,
comparison, summaries (min/max), inclusion in data frames,
subscripting, and printing. The classes can hold a vector of such
representations.

`getRversion`

returns the version of the running R as an R
system version object.

The `[[`

operator extracts or replaces a single version. To
access the integers of a version use two indices: see the examples.

`compareVersion`

;
`packageVersion`

for the version of a specific R package.
`R.version`

etc for the version of R (and the information
underlying `getRversion()`

).

# NOT RUN { x <- package_version(c("1.2-4", "1.2-3", "2.1")) x < "1.4-2.3" c(min(x), max(x)) x[2, 2] x$major x$minor if(getRversion() <= "2.5.0") { ## work around missing feature cat("Your version of R, ", as.character(getRversion()), ", is outdated.\n", "Now trying to work around that ...\n", sep = "") } x[[c(1, 3)]] # '4' as a numeric vector, same as x[1, 3] x[1, 3] # 4 as an integer x[[2, 3]] <- 0 # zero the patchlevel x[[c(2, 3)]] <- 0 # same x x[[3]] <- "2.2.3"; x x <- c(x, package_version("0.0")) is.na(x)[4] <- TRUE stopifnot(identical(is.na(x), c(rep(FALSE,3), TRUE)), anyNA(x)) # }