R If Statement

R If Statement

In this tutorial, we will learn about if statements in R. We will cover the basics of conditional execution using if statements.

What is an If statement

An if statement is a conditional statement that executes a block of code if a specified condition is true.

Syntax

The syntax for the if statement in R is:

if (condition) {
    # Code block to execute if condition is true
}

The if statement evaluates the specified condition. If the condition is true, the code block inside the if statement is executed; otherwise, it is skipped.

The following is the flowchart of how execution flows from start to the end of an if statement.

Flowchart of If Statement

Checking if a Number is Even

In R, checking if a number is even can be done using the modulo operator (%), where the remainder when divided by 2 is zero.

For example,

  1. Declare a variable num.
  2. Assign a value to num.
  3. Use an if statement to check if num is even.
  4. Print a message indicating whether num is even or not.

R Program

num <- 10
if (num %% 2 == 0) {
    print(paste(num, 'is even.'))
}

Output

[1] "10 is even."

Checking if a String Starts with a Specific Value

In R, checking if a string starts with a specific value can be done using the startsWith() function. The function returns a boolean value, which can be used as a condition in the if statement.

For example,

  1. Declare a variable str.
  2. Assign a value to str.
  3. Use an if statement to check if str starts with a specific value.
  4. Print a message indicating the result of the check.

R Program

str <- 'Hello, world!'
if (startsWith(str, 'Hello')) {
    print('String starts with "Hello".')
}

Output

[1] "String starts with \"Hello\"."

Checking if a Number is Positive

In R, checking if a number is positive within an if statement involves evaluating the condition where the number is greater than zero using the greater than operator (>).

For example,

  1. Declare a variable num.
  2. Assign a value to num.
  3. Use an if statement to check if num is positive.
  4. Print a message indicating whether num is positive or not.

R Program

num <- -5
if (num > 0) {
    print(paste(num, 'is positive.'))
}

Output