Unlocking the Power of R Variables and Constants
What are R Variables?
In the world of computer programming, a variable is a named storage location where data is held. Think of it like a labeled box where you can store a value. In R programming, variables are essential for storing and manipulating data. For instance, you can assign the value 13.8 to a variable named x, and whenever you use x in your program, you’ll get 13.8 as the output.
Declaring R Variables: The Rules
When creating a variable in R, you can use any name you like, but there are some rules to follow:
- Variable names can consist of letters, digits, periods, and underscores.
- You can start a variable name with a letter or a period, but not with digits.
- If a variable name starts with a dot, you can’t follow it with digits.
- R is case sensitive, meaning
ageandAgeare treated as different variables. - Some reserved words can’t be used as variable names.
Types of R Variables
R variables can be categorized into five types based on the data they store:
- Boolean Variables: Store single-bit data, either TRUE or FALSE.
- Integer Variables: Store numeric data without decimal values.
- Floating Point Variables: Store numeric data with decimal values.
- Character Variables: Store single character data.
- String Variables: Store data composed of more than one character.
Changing Variable Values
The value of a variable can be changed anytime based on conditions or information passed into the program. For example, you can initially set a variable message to “Hello World!” and then change it to “Welcome to Programiz!”.
R Constants: Unchangeable Values
Constants are entities whose values shouldn’t be changed throughout the code. In R, you can declare constants using the <- symbol. Constants can be divided into five types:
- Integer Constants: Integer values ending with the letter L.
- Numeric Constants: Integers, floating-point numbers, or exponential numbers.
- Logical Constants: Either TRUE or FALSE.
- String Constants: String data used in the code.
- Complex Constants: Data containing a real and an imaginary part.
Special R Constants
R programming provides four special types of constants:
- NULL: Represents an empty R object.
- Inf/-Inf: Represents positive and negative infinity.
- NaN (Not a Number): Represents undefined numerical values.
- NA: Represents values that are not available.
Built-In R Constants
R programming offers some predefined constants that can be directly used in your program, such as:
- LETTERS: Displays a list of all uppercase letters.
- letters: Displays a list of all small letters.
- month.abb: Prints 3-letter abbreviations of all English months.
- pi: Prints the numerical value of the constant pi.
With this comprehensive guide, you’re now equipped to harness the power of R variables and constants to take your programming skills to the next level!