Variables are used to organize and store data in R programming. The assignment operator (- or =) is used to assign values to variables. Here are some essential ideas regarding variables in R:
Names of variables:
- MyVariable and myvariable are separate variables in R because of the case-sensitivity of variable names.
- Letters, digits, or underscores must come before a dot (.) or a letter to begin a variable name.If it starts with period(.), it cannot be followed by a digit.
- Choosing variable names that are descriptive and express the meaning of the data they contain is a smart practice.
- Reserved words cannot be used as variables (TRUE, FALSE, NULL, if…)
- A variable name cannot start with a number or underscore (_)
# Legal variable names:
myvar <- “technoexcel”
my_var <- “technoexcel””
myVar <- “technoexcel””
MYVAR <- “technoexcel””
myvar2 <- “technoexcel””
.myvar <- “technoexcel””
# Illegal variable names:
2myvar <- “technoexcel””
my-var <- “technoexcel””
my var <- “technoexcel””
_my_var <- “technoexcel””
my_v@ar <- “technoexcel”
TRUE <- “technoexcel”
Assignment:
- You can assign values to variables using the <- operator or the = operator. For example:
x <- 10
y = “Hello, World!”
Data Types:
- R is a dynamically-typed language, which means that variables can change their data type as you assign different values to them.
- Common data types in R include numeric (e.g., integers or floating-point numbers), character (e.g., strings), logical (e.g., TRUE or FALSE), and more complex types like lists, data frames, and factors.
Checking Variable Types:
- You can check the data type of a variable using the class() function. For example:
class(x) # Returns “numeric”
class(y) # Returns “character”
Vectors:
- R is particularly well-suited for working with vectors (arrays) of data. You can create vectors and assign them to variables. For example:
numbers <- c(1, 2, 3, 4, 5)
Global vs. Local Scope:
- Variables can have either global or local scope.
- Global variables are accessible throughout your R session.
- Local variables are defined within a function and are only accessible within that function’s scope.
Removing Variables:
- You can remove a variable using the rm() function. For example:
rm(x) # Removes the variable x
Constants:
- While R doesn’t have built-in support for constants, it’s a convention to use uppercase variable names to indicate that a variable should not be modified as if it were a constant.
Here are some additional examples of variable usage in R:
# Creating variables
age <- 30
name <- “John Doe”
is_student <- TRUE
# Mathematical operations with variables
x <- 5
y <- 3
sum_result <- x + y
In summary, variables in R are used to store and manipulate data, and they play a central role in programming with the language.
