How to write if and else if in R?

Recipe Objective

Conditional statements control the flow of the program. There are some cases where you need to execute a function only when a certain condition is met and some different function if it is not. We can carry out this task using if...else statements in R.

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Nested if..else if...else statements is one type of statement where you check multiple conditions and execute the functions accordingly. This recipe demonstrates how to use the nested if..else statements.

Syntax:

if (boolean_expression1) { // statements you want to execute if the if the boolean expression1 is TRUE } else if (boolean_expression2) { // statements you want to execture if the boolean_expression2 is TRUE } else { // statements you want to execute if all the above conditions are False }

Example: We will check different elements present in the vector using nested if..else statement

Step 1: Create a numeric vector

vec_ = c("Rome", "Mumbai", "NewYork", "Edinburgh")

Step 2: Nested if..else if..else

We will use %in% operator in the boolean expression to check the elements present in the vector

if ("Delhi" %in% vec_){ print("Delhi is present in the vector") } else if ("NewYork" %in% vec_){ print("New York is present in the vector ") } else { print("New York and Delhi not present in the vector ") }

[1] "New York is present in the vector "