What is the difference between library and require functions in R

Question

I do not understand the difference between two of these. Please help someone.

Answer 1

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)

}

}