A variable is created to reserve some memory spaces. The reserved memory space depends upon the type of data to be stored within the defined variable. The data is stored in a variable to perform various operations on that data, as per the requirement. The data stored in a variable can be manipulated to get the desired result.
Valid and Invalid Variable Name:
A variable name in R is valid if the first letter of the variable name is a letter or a dot not followed by a number and the name of the variable contains letters, numbers, dots and underline characters only. For all other cases, the name of a variable in R is invalid.
Example: Validity of a Variable Name:
| Variable Name | Valid/Invalid | Explanation |
|---|---|---|
| 7var_name | Invalid | In R programming, the name of a variable can not start with a numeric digit. |
| _var_name | Invalid | In R programming, the name of a variable can not start with an underscore(_). |
var_nam
| Invalid |
In R programming, the name of a variable can not include any special character other than a dot(.) and underscore(_). |
|
| .5var_name | Invalid | In R programming, the name of a variable can not start with a dot(.) followed by a numeric value. |
| var_name | Valid | A variable name in R is valid if the first letter of the variable name is a letter or a dot not followed by a number and the name of the variable contains letters, numbers, dots and underline characters only. |
| var.name | Valid | A variable name in R is valid if the first letter of the variable name is a letter or a dot not followed by a number and the name of the variable contains letters, numbers, dots and underline characters only. |
| var_name2 | Valid | A variable name in R is valid if the first letter of the variable name is a letter or a dot not followed by a number and the name of the variable contains letters, numbers, dots and underline characters only. |
Assignment of variables:
The leftward, rightward, and equal_to operators are used for the assignment of values to a variable in R.
Printing the value of the variable:
The print() and cat() functions are used to print the value of the variable in R.
Multiple values can be combined into a continued print output using the cat() function.
Example: Assignment of variables in R:
# Assignment using equal operator. var1 = 543 # Assignment using the leftward operator. var2 <- "Transformation is the key." # Assignment using the rightward operator. 555L -> var3 print(var1) cat ("var1 is ", var1,"\n") cat ("var2 is ", var2,"\n") cat ("var3 is ", var3,"\n") |
The data type of variables in R:
Data Types are used to define the type of data that is to be stored in a variable. Depending on the type of data, the memory space is allotted to a variable by the operating system. Unlike programming languages, such as C++, R is a dynamically typed programming language. C++, on the other hand, is statically typed. In a dynamically typed programming language, the data type of a variable is checked during the execution of the respective statement. This also means that the data type of a variable can be changed multiple times in R programs. There is no static data type for a variable in R.
To check the data type of a variable in R:
In R programming, the class() function is used to serve this purpose.
Example: Verification of the data type of a variable in R:
var_1<- 666
cat("Data type of var_1 is ",class(var_1),"\n")
var_1<- "Data type of variables in R"
cat("Data type of var_1 is ",class(var_1),"\n")
var_1<- 200L
cat("Data type of var_1 is ",class(var_1),"\n")
