R Course


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In R, a variable is either a function or a value. You must use a <- 5 to assign 5 to the variable a.

a <- "test"
b <- 5

# you can use assign 
# to change a variable value
assign(a, b)
# or simply use
a <- 7

Using "="

You can also use =, but you should not, as this is overusing an operator that is supposed to do something else.

You can read the official note here.

Declare a variable

You can't declare a variable without giving it a value, but you can do something like this

r <- NULL

This is useful, as concatenating with NULL is working well

r <- NULL
r <- c(r, 3)
# [1] 3

Print a variable

In R, every line is an expression. And if the result of the expression is a value, then it's printed, otherwise, you need to explicitly call print (or any printing function like cat).

r # implicit

print(r) # explicit