pkg_attach() is a vectorized version of library() over
the package argument to attach multiple packages in a single function
call. pkg_load() is a vectorized version of
requireNamespace() to load packages (without attaching them).
The functions pkg_attach2() and pkg_load2() are wrappers of
pkg_attach(install = TRUE) and pkg_load(install = TRUE),
respectively. loadable() is an abbreviation of
requireNamespace(quietly = TRUE).
pkg_attach(..., install = FALSE, message = getOption("xfun.pkg_attach.message", TRUE))pkg_load(..., error = TRUE, install = FALSE)
loadable(pkg, strict = TRUE, new_session = FALSE)
pkg_attach2(...)
pkg_load2(...)
Package names (character vectors, and must always be quoted).
Whether to automatically install packages that are not
available using install.packages(). You are recommended to
set a CRAN mirror in the global option repos via
options() if you want to automatically install packages.
Whether to show the package startup messages (if any startup messages are provided in a package).
Whether to signal an error when certain packages cannot be loaded.
A single package name.
If TRUE, use requireNamespace() to test if
a package is loadable; otherwise only check if the package is in
.packages(TRUE) (this does not really load the package, so it
is less rigorous but on the other hand, it can keep the current R session
clean).
Whether to test if a package is loadable in a new R
session. Note that new_session = TRUE implies strict = TRUE.
pkg_attach() returns NULL invisibly. pkg_load()
returns a logical vector, indicating whether the packages can be loaded.
These are convenience functions that aim to solve these common problems: (1)
We often need to attach or load multiple packages, and it is tedious to type
several library() calls; (2) We are likely to want to install the
packages when attaching/loading them but they have not been installed.
# NOT RUN {
library(xfun)
pkg_attach("stats", "graphics")
# pkg_attach2('servr') # automatically install servr if it is not installed
(pkg_load("stats", "graphics"))
# }
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