| library() |
require() |
- Library () function gives an error message display, if the desired package cannot be loaded.
|
- Require () function is used inside function and throws a warning messages whenever a particular package is not Found
|
- It loads the packages whether it is already loaded or not,
|
- It just checks that it is loaded, or loads it if it isn’t (use in functions that rely on a certain package). The documentation explicitly states that neither function will reload an already loaded package.
|
Consider a related program for the above differentiation.
if(!require(package, character.only=T, quietly=T)) {
install.packages (package)
library(package, character.only=T)
}
For multiple packages you can use
for(package in c(”, ”)) {
if(!require(package, character.only=T, quietly=T)) {
install.packages (package)
library(package, character.only=T)
}
}