Next and break statements in R Programming - Step-by-Step Execution

Concept Flow - Next and break statements

Start Loop

↓

Check Condition

Yes↓

Inside Loop

↓

Next?

↓

Skip Rest

Back to Condition↓

End Loop

↩Back to Condition

The loop starts and checks the condition. Inside the loop, if 'next' is triggered, it skips to the next iteration. If 'break' is triggered, it exits the loop immediately.

Execution Sample

R Programming

for(i in 1:5) {
  if(i == 2) next
  if(i == 4) break
  print(i)
}

This loop prints numbers 1 to 5 but skips 2 and stops before printing 4.

Execution Table

Iteration	i	Condition i==2	Action	Output
1	1	False	print(1)	1
2	2	True	next (skip print)
3	3	False	print(3)	3
4	4	False	break (exit loop)
-	-	-	-	Loop ends, no more iterations

💡 At iteration 4, break is triggered, so the loop stops immediately.

Variable Tracker

Variable	Start	After 1	After 2	After 3	After 4	Final
i	-	1	2	3	4	Loop ends

Key Moments - 2 Insights

Why does the loop skip printing when i equals 2?

Because at iteration 2, the condition i==2 is True, so 'next' is executed which skips the rest of the loop body including print, as shown in execution_table row 2.

Why does the loop stop before printing 4?

At iteration 4, the condition i==4 is True, so 'break' is executed which immediately exits the loop, stopping any further iterations or printing, as shown in execution_table row 4.

Visual Quiz - 3 Questions

Look at the execution table, what is the value of i when the loop skips printing?

A 4

B 2

C 3

D 1

💡 Hint

Check the 'Action' column where 'next' is triggered and see the corresponding 'i' value.

At which iteration does the loop stop executing?

A 4

B 3

C 5

D 2

💡 Hint

Look for the 'break' action in the execution_table and note the iteration number.

If we remove the 'next' statement, what will be printed?

A 1, 2, 3, 4

B 1, 3

C 1, 2, 3

D 1, 2, 3, 4, 5

💡 Hint

Without 'next', the loop will print all numbers until 'break' stops it at 4, so 1, 2, 3 will print.

Concept Snapshot

for(i in 1:n) {
  if(condition) next  # skips to next iteration
  if(condition) break # exits loop immediately
  # code here runs only if no next or break
}
Use 'next' to skip, 'break' to stop loop early.

Full Transcript

This example shows how 'next' and 'break' work inside a loop in R. The loop runs from 1 to 5. When i equals 2, 'next' skips printing 2 and moves to the next iteration. When i equals 4, 'break' stops the loop completely, so 4 and 5 are not printed. Variables change each iteration, and the loop flow depends on these statements to skip or stop early.

Practice

1. What does the next statement do inside a loop in R?

easy

A. Skips the current iteration and moves to the next one

B. Stops the entire loop immediately

C. Restarts the loop from the beginning

D. Exits the current function

Solution

1. Step 1: Understand the purpose of next

   The next statement is used to skip the rest of the current loop iteration and continue with the next iteration.

2. Step 2: Compare with other statements

   Unlike break, which stops the loop completely, next only skips to the next round.

3. Final Answer:

   Skips the current iteration and moves to the next one -> Option A

4. Quick Check:

   next skips iteration [OK]

Hint: Remember: next skips iteration, break stops loop [OK]

Common Mistakes:

• Confusing next with break
• Thinking next restarts the loop
• Believing next exits the function

2. Which of the following is the correct syntax to skip the current iteration in a for loop in R?

easy

A. skip

B. continue

C. break

D. next

Solution

1. Step 1: Recall R loop control keywords

   In R, the keyword to skip the current iteration is next. There is no continue keyword in R.

2. Step 2: Identify correct keyword

   break stops the loop, skip is not a valid keyword.

3. Final Answer:

   next -> Option D

4. Quick Check:

   Use next to skip iteration [OK]

Hint: Use 'next' to skip, not 'continue' in R [OK]

Common Mistakes:

• Using 'continue' instead of 'next'
• Using 'skip' which is invalid
• Confusing 'break' with skipping iteration

3. What will be the output of the following R code?

for(i in 1:5) {
  if(i == 3) next
  print(i)
}

medium

A. [1] 1 2 4 5

B. [1] 1 2 3 4 5

C. [1] 1 2 3 4

D. [1] 1 2 3 4 5 3

Solution

1. Step 1: Analyze the loop and condition

   The loop runs from 1 to 5. When i == 3, the next statement skips printing 3.

2. Step 2: Determine printed values

   Values 1, 2, 4, and 5 are printed. The number 3 is skipped.

3. Final Answer:

   [1] 1 2 4 5 -> Option A

4. Quick Check:

   next skips 3, so output excludes 3 [OK]

Hint: next skips printing 3, so output misses 3 [OK]

Common Mistakes:

• Including 3 in output
• Thinking next stops loop
• Confusing output format

4. Identify the error in this R code snippet:

for(i in 1:5) {
  if(i == 4) next()
  print(i)
}

medium

A. The loop variable i is not defined

B. Using parentheses with next causes an error

C. print() cannot be used inside loops

D. The if condition syntax is incorrect

Solution

1. Step 1: Check usage of next statement

   In R, next is a statement, not a function, so it should not have parentheses.

2. Step 2: Identify syntax error

   Using next() causes a syntax error. Correct usage is just next.

3. Final Answer:

   Using parentheses with next causes an error -> Option B

4. Quick Check:

   next is not a function, no parentheses [OK]

Hint: Don't add () after next; it's not a function [OK]

Common Mistakes:

• Writing next() instead of next
• Assuming next is a function
• Misreading error cause

5. Consider the following R code:

sum <- 0
for(i in 1:10) {
  if(i %% 2 == 0) next
  if(i > 7) break
  sum <- sum + i
}
print(sum)

What is the output of this code?

hard

A. 25

B. 20

C. 16

D. 30

Solution

1. Step 1: Understand loop conditions

   The loop runs from 1 to 10. It skips even numbers with next. It stops completely when i > 7 due to break.

2. Step 2: Calculate sum of odd numbers less than or equal to 7

   Odd numbers before break: 1, 3, 5, 7. Sum = 1+3+5+7 = 16.

3. Final Answer:

   16 -> Option C

4. Quick Check:

   Sum odd < 8 = 16 [OK]

Hint: Sum odd numbers until i > 7, skip evens [OK]

Common Mistakes:

• Including even numbers in sum
• Ignoring break condition
• Summing all numbers 1 to 10