For Loop in R

In this tutorial, we will learn about for loops in R. We will cover the basics of iterative execution using for loops.

What is a For Loop

A for loop is a control flow statement that allows code to be executed repeatedly based on a given Boolean condition. The loop is typically used when the number of iterations is known before entering the loop.

Syntax

The syntax for the for loop in R is:

for (item in iterable) {
    # Code block to be executed
}

The for loop iterates over each item in the iterable object (such as a vector, list, or data frame) and executes the code block for each item.


Example 1: Printing Numbers from 1 to 10

  1. Use a for loop to print numbers from 1 to 10.

R Program

for (i in 1:10) {
    cat(i, " ", sep = "")
}

Output

1 2 3 4 5 6 7 8 9 10

Example 2: Calculating the Factorial of a Number

  1. Use a for loop to calculate the factorial of a number.

R Program

n <- 5
factorial <- 1
for (i in 1:n) {
    factorial <- factorial * i
}
cat("Factorial of", n, "is", factorial)

Output

Factorial of 5 is 120

Example 3: Summing the Elements of a Vector

  1. Use a for loop to calculate the sum of the elements in a vector.

R Program

arr <- c(1, 2, 3, 4, 5)
sum <- 0
for (num in arr) {
    sum <- sum + num
}
cat("Sum of the elements in the vector is", sum)

Output

Sum of the elements in the vector is 15