R Decision Making
In R programming, Decision Making statements help to decide whether to execute a block of code or not, based on a condition. Decision making is an important aspect in any programming language. Decision Making statements are also called Conditional statement.
In this tutorial, we list out decision making statements available in R language, and go through examples for each of them.
The following are detailed tutorials for each of the decision making statements in R.
R If Statement
In If statement, a condition (boolean expression) is evaluated. If the result is TRUE, then a block of statements are executed.
Example.R
a <- 6 if (a == 6) { print("a is 6.") } print("End of program.")
Output
[1] "a is 6." [1] "End of program."
If the condition evaluates to FALSE, then if-block is not executed, and the execution continues with the statements after If statement.
Example.R
a <- 10 if (a == 6) { print("a is 6.") } print("End of program.")
Output
[1] "End of program."
R If-Else Statement
A boolean expression is evaluated and if TRUE, statements in if-block are execute, otherwise else-block statements are executed.
Example.R
a <- 10 if (a == 6) { print("a is 6.") } else { print("a is not 6.") } print("End of program.")
Output
[1] "a is not 6." [1] "End of program."
R If-Else-If Statement
This is kind of a chained if-else statement. From top to down, whenever a condition evaluates to TRUE, corresponding block is executed, and the control exits from this if-else-if statement.
Example.R
a <- 10 if (a == 6) { print("a is 6.") } else if (a == 10) { print("a is 10.") } else if (a == 20) { print("a is 20.") } print("End of program.")
Output
[1] "a is 10." [1] "End of program."
R Switch Statement
In R Switch statement, an expression is evaluated and based on the result, a value is selected from a list of values.
Example.R
y <- 3 x <- switch( y, "Good Morning", "Good Afternoon", "Good Evening", "Good Night" ) print(x)
Output
[1] "Good Evening"
Conclusion
In this R tutorial, we learned about R decision making / conditional statements – If, If-Else, If-Else-If, and Switch.