# This is a comment
a = 4 # single statement
a = 4; b = 3; c = b # multiple statements
# R has a dynamic type system; you can define a variable without declaring its
# type explicitly and you can change the variable's type in the same session:
a = 3.2
a = "foo"
a <- 4 # another way to assign value
# Here are a few different ways to display the value of a variable:
a = 4
print(a)
a # same thing
cat(a) # same thing
# cat can print multiple variables one after the other
cat("The value of the variable a is: ", a)
# Here are some important commands with short explanations:
x = 3 # assign value 3 to variable x
y = 3 * x + 2 # basic variable assignment and arithmetic
ratio.of.x.and.y = x / y # divide x by y and assign result
ls() # list variable names in workspace memory
ls(all.names = TRUE) # list all variables including hidden ones
ls.str() # print annotated list of variable names
save.image(file = "file-name") # save all variables to a file
save(x, y, file = "varFile") # save specified variables
rm(x, y) # clear variables x and y from memory
rm(list = ls()) # clear all variables in workspace memory
load("varFile") # load variables from file back to the workspace
cat(x)
