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We use the R `break` and `next` statements to alter the flow of a program. These are also known as jump statements in programming:

• `break` – terminate a looping statement
• `next` – skips an iteration of the loop

## R break Statement

You can use a `break` statement inside a loop (`for`, `while`, `repeat`) to terminate the execution of the loop. This will stop any further iterations.

The syntax of the `break` statement is:

```if (test_expression) {
break
}```

The `break` statement is often used inside a conditional (`if...else`) statement in a loop. If the condition inside the `test_expression` returns `True`, then the `break` statement is executed. For example,

```# vector to be iterated over
x = c(1, 2, 3, 4, 5, 6, 7)

# for loop with break statement
for(i in x) {

# if condition with break
if(i == 4) {
break
}

print(i)
}```

Output

``` 1
 2
 3```

Here, we have defined a vector of numbers from `1` to `7`. Inside the `for` loop, we check if the current number is `4` using an `if` statement.

If yes, then the `break` statement is executed and no further iterations are carried out. Hence, only numbers from `1` to `3` are printed.

## break Statement in Nested Loop

If you have a nested loop and the `break` statement is inside the inner loop, then the execution of only the inner loop will be terminated.

Let's check out a program to use break statements in a nested loop.

```# vector to be iterated over
x = c(1, 2, 3)
y = c(1, 2, 3)

# nested for loop with break statement
for(i in x) {
for (j in y) {
if (i == 2 & j == 2) {
break
}
print(paste(i, j))
}
}```

Output

``` "1 1"
 "1 2"
 "1 3"
 "2 1"
 "3 1"
 "3 2"
 "3 3"```

Here, we have a `break` statement inside the inner loop.

We have used it inside a conditional statement such that if both the numbers are equal to `2`, the inner loop gets terminated.

The flow then moves to the outer loop. Hence, the combination `(2, 2)` is never printed.

## R next Statement

In R, the `next` statement skips the current iteration of the loop and starts the loop from the next iteration.

The syntax of the `next` statement is:

```if (test_condition) {
next
}```

If the program encounters the `next` statement, any further execution of code from the current iteration is skipped, and the next iteration begins.

Let's check out a program to print only even numbers from a vector of numbers.

```# vector to be iterated over
x = c(1, 2, 3, 4, 5, 6, 7, 8)

# for loop with next statement
for(i in x) {

# if condition with next
if(i %% 2 != 0) {
next
}

print(i)
}```

Output

``` 2
 4
 6
 8```

Here, we have used an `if` statement to check whether the current number in the loop is odd or not.

If yes, the `next` statement inside the if block is executed, and the current iteration is skipped.