Loading multiple R packages with a single command

问题

Multiple R packages may be loaded using the function p_load function from pacman R package with the following command:

pacman::p_load("ggplot2", "lme4")

However, I want to use the command like this

Packages <- c("ggplot2", "lme4")
pacman::p_load(Packages)

which does not work. Wonder how this can be achieved?

回答1:

Set character.only on TRUE

Packages <- c("ggplot2", "lme4")
Packages %in% loadedNamespaces() # check if the packages are loaded
# [1] FALSE FALSE

pacman::p_load(Packages, character.only = TRUE)

Packages %in% loadedNamespaces()
# [1] TRUE TRUE

From ?p_load:

"character.only : logical. If TRUE then p_load will only accept a single input which is a character vector containing the names of packages to load."

回答2:

Alternatively, do do.call(p_load, packages).

You can also do this without Pacman:

lapply(packages, require, character.only = TRUE)

But as others have said, not recommended because it reduces clarity.

回答3:

Use argument char in p_load function.

char: Character vector containing packages to load

foo <- c("data.table", "ggplot2")
pacman::p_load(char = foo)

来源：https://stackoverflow.com/questions/45509485/loading-multiple-r-packages-with-a-single-command