The `for` statement in R is a bit different from what you usually use in other programming languages.

Rather than iterating over a numeric progression, R’s `for` statement iterates over the items of a vector or a list.

The items are iterated in the order that they appear in the vector.

## Syntax

Here’s the syntax of the `for` statement:

vector is a collection of objects that can be iterated over

statement(s) are executed once for each item in a vector

var takes items from a vector one by one

## Basic Examples

Example: Iterate through a vector

``````> colors <- c("red","green","blue","yellow")
> for (x in colors) {
+   print(x)
+ }
 "red"
 "green"
 "blue"
 "yellow"
``````

Example: Iterate through a list

``````> l <- list(3.14, "Hi", c(1,2,3))
> for (x in l) {
+   print(x)
+ }
 3.14
 "Hi"
 1 2 3
``````

If you need to execute a group of statements for a specified number of times, use sequence operator `:` or built-in function `seq()`

Example: Print ‘Hello!’ 3 times

``````> for (x in 1:3) {
+   print("Hello!")
+ }
 "Hello!"
 "Hello!"
 "Hello!"
``````

Example: Iterate a sequence and square each element

``````> for (x in seq(from=2,to=8,by=2)) {
+   print(x^2)
+ }
 4
 16
 36
 64
``````

## for Loop Without Curly Braces

If you have only one statement to execute, you can skip curly braces.

Example: Print the numbers 0 to 4

``````> for (x in 0:4) print(x)
 0
 1
 2
 3
 4
``````

## Nested for loop

A nested `for` loop is a loop within a loop.

They are useful for when you want to repeat something several times for several things.

Example:

``````> for(x in 1:3) {
+   for(y in 1:2) {
+     print(paste(x, y))
+   }
+ }
 "1 1"
 "1 2"
 "2 1"
 "2 2"
 "3 1"
 "3 2"
``````

## Break in for Loop

In R, `break` statement is used to exit the loop immediately.

It simply jumps out of the loop altogether, and the program continues after the loop.

Example: Break the loop at ‘blue’

``````> colors <- c("red","green","blue","yellow")
> for (x in colors) {
+   if (x == "blue")
+     break
+   print(x)
+ }
 "red"
 "green"
``````

## Next (continue) in for Loop

The next statement skips the current iteration of a loop and continues with the next iteration.

Example: Skip ‘blue’ using continue statement

``````> colors <- c("red","green","blue","yellow")
> for (x in colors) {
+   if (x == "blue")
+     next
+   print(x)
+ }
 "red"
 "green"
 "yellow"
``````