package_dependencies Computations on the Dependency Hierarchy of Packages

Description

Find (recursively) dependencies or reverse dependencies of packages.

Usage

package_dependencies(packages = NULL, db = NULL, which = "strong",
	             recursive = FALSE, reverse = FALSE,
                     verbose = getOption("verbose"))

Arguments

packages	a character vector of package names.
db	character matrix as from available.packages() (with the default NULL the results of this call) or data frame variants thereof. Alternatively, a package database like the one available from https://cran.r-project.org/web/packages/packages.rds.
which	a character vector listing the types of dependencies, a subset of c("Depends", "Imports", "LinkingTo", "Suggests", "Enhances"). Character string "all" is shorthand for that vector, character string "most" for the same vector without "Enhances", character string "strong" (default) for the first three elements of that vector.
recursive	a logical indicating whether (reverse) dependencies of (reverse) dependencies (and so on) should be included, or a character vector like which indicating the type of (reverse) dependencies to be added recursively.
reverse	logical: if FALSE (default), regular dependencies are calculated, otherwise reverse dependencies.
verbose	logical indicating if output should monitor the package search cycles.

Value

Named list with one element for each package in argument packages, each consists of a character vector naming the (recursive) (reverse) dependencies of that package.

For given packages which are not found in the db, NULL entries are returned, as opposed to character(0) entries which indicate no dependencies.

See Also

dependsOnPkgs.

Examples

myPkgs <- c("MASS", "Matrix", "KernSmooth", "class", "cluster", "codetools")
pdb <- available.packages()
system.time(
dep1 <- package_dependencies(myPkgs, db = pdb) # all arguments at default
) # very fast
utils::str(dep1, vec.len=10)

system.time( ## reverse dependencies, recursively --- takes much longer:
deps <- package_dependencies(myPkgs, db = pdb, which = "most",
                             recursive = TRUE, reverse = TRUE)
) # seen ~ 10 seconds

lengths(deps) # 2020-05-03: all are 16053, but codetools with 16057

## install.packages(dependencies = TRUE) installs 'most' dependencies
## and the strong recursive dependencies of these: these dependencies
## can be obtained using 'which = "most"' and 'recursive = "strong"'.
## To illustrate on the the first packages with non-missing Suggests:
packages <- pdb[head(which(!is.na(pdb[, "Suggests"]))), "Package"]
package_dependencies(packages, db = pdb,
                     which = "most", recursive = "strong")