Functions in R are stored in the same way as other objects are, with the <- assignment, with a structure like so:
FUNCTIONNAME <- function(ARGUMENTS) { ACTIONS }
If you've created functions in JavaScript you'll notice that it's a very similar structure. Here's a working example:
add2numbers <- function(num1, num2) {
total <- num1 + num2
return (total)
}
If-else statements in R can test something about your data and initiate different actions depending on whether the test is met or not.
The structure of an if-else statement is as follows:
if (CONDITION TO TEST) { DO THIS IF RESULT IS TRUE }
else { DO THIS IF RESULT IS FALSE}
Here's an example that works:
if (mynumber > 50) { print("good") } else { print("not so good")}
If the expression is all on one line you can also omit the curly brackets and write it more simply like so:
if (mynumber > 50) print("good") else print("not so good")
If you don't want to squeeze it onto one line, it can be easier to read if you split it across multiple lines like so:
if (mynumber > 50) {
print("good")
}
else {
print("not so good")
}
You don't have to use just one 'if' in an if-else statement: you can have multiple tests using else if like so:
if (mynumber > 50) { print("good") } else if (mynumber < 25) { print("poor")} else {print ("average")}