Break, next, and redo behavior in Ruby - Mini Project: Build & Apply

Break, next, and redo behavior

📖 Scenario: You are working on a simple program that processes a list of tasks. Sometimes you want to skip a task, stop processing early, or retry a task if it fails.

🎯 Goal: Build a Ruby program that demonstrates how to use break, next, and redo inside a loop to control the flow of task processing.

📋 What You'll Learn

Create an array called tasks with the exact values: ['clean', 'cook', 'shop', 'laundry', 'study']

Create a variable called skip_task and set it to the string 'shop'

Use a for loop with variable task to iterate over tasks and inside the loop:

Use next to skip the task if it matches skip_task

Use redo to retry the task 'laundry' once before moving on

Use break to stop the loop completely if the task is 'study'

Print each task when it is processed

💡 Why This Matters

🌍 Real World

Controlling loops with break, next, and redo is useful when processing lists of jobs, filtering data, or retrying failed operations in real programs.

💼 Career

Understanding these flow controls helps in debugging, writing efficient loops, and managing complex workflows in software development.

1

Create the tasks array

Create an array called tasks with these exact string values: 'clean', 'cook', 'shop', 'laundry', and 'study'

Ruby

# Create the tasks array
# Your code here

Hint

Use square brackets [] to create an array and separate items with commas.

2

Add the skip_task variable

Create a variable called skip_task and set it to the string 'shop'

Ruby

tasks = ['clean', 'cook', 'shop', 'laundry', 'study']
# Create skip_task variable
# Your code here

Hint

Assign the string 'shop' to the variable skip_task.

3

Loop through tasks and skip the skip_task

Use a for loop with variable task to iterate over tasks. Inside the loop, use next to skip the task if it matches skip_task. Print each task that is processed.

Ruby

tasks = ['clean', 'cook', 'shop', 'laundry', 'study']
skip_task = 'shop'

# Loop through tasks and skip the skip_task
# Your code here

Hint

Use next to skip the current loop iteration when task equals skip_task.

4

Add redo and break behavior

Modify the loop to retry the task 'laundry' once using redo. Also, use break to stop the loop completely if the task is 'study'. Print each task when it is processed.

Ruby

tasks = ['clean', 'cook', 'shop', 'laundry', 'study']
skip_task = 'shop'

for task in tasks
  # Add redo and break behavior here
  # Your code here
end

Hint

Use a hash redo_counts to track retries. Use redo to repeat the 'laundry' task once. Use break to stop when task is 'study'.

Practice

1. What does the break keyword do inside a Ruby loop?

easy

A. Stops the loop completely and exits it

B. Skips the current iteration and moves to the next

C. Repeats the current iteration without moving forward

D. Pauses the loop until a condition is met

Solution

1. Step 1: Understand the role of break

   The break keyword immediately stops the loop and exits it, no further iterations happen.

2. Step 2: Compare with other keywords

   next skips to the next iteration, redo repeats the current one, but break stops all looping.

3. Final Answer:

   Stops the loop completely and exits it -> Option A

4. Quick Check:

   break = stop loop [OK]

Hint: Break means stop the loop right away [OK]

Common Mistakes:

• Confusing break with next
• Thinking break repeats iteration
• Assuming break pauses instead of stops

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

easy

A. break

B. next

C. redo

D. skip

Solution

1. Step 1: Identify the keyword for skipping iteration

   The keyword next is used in Ruby to skip the rest of the current loop iteration and move to the next one.

2. Step 2: Check other options

   break stops the loop, redo repeats the current iteration, and skip is not a Ruby keyword.

3. Final Answer:

   next -> Option B

4. Quick Check:

   Skip iteration = next [OK]

Hint: Use next to jump to next loop step [OK]

Common Mistakes:

• Using break instead of next
• Trying to use skip keyword (not valid)
• Confusing redo with next

3. What is the output of this Ruby code?

i = 0
while i < 3
  i += 1
  if i == 2
    redo
  end
  puts i
end

medium

A. 1 2 2 2 ... (infinite loop)

B. 1 3

C. 1 2 3

D. 1 3 3

Solution

1. Step 1: Trace the loop and redo behavior

   When i == 2, redo repeats the current iteration without incrementing i again, causing the loop to print 2 repeatedly.

2. Step 2: Understand infinite repetition

   Since i is not changed inside the redo loop, it never moves past 2, causing an infinite loop printing 2 repeatedly.

3. Final Answer:

   1 2 2 2 ... (infinite loop) -> Option A

4. Quick Check:

   redo repeats current step causing infinite loop [OK]

Hint: Redo repeats current step, watch for infinite loops [OK]

Common Mistakes:

• Assuming i increments inside redo
• Thinking redo skips iteration
• Ignoring infinite loop possibility

4. Find the error in this Ruby code snippet:

for i in 1..3
  if i == 2
    next
  elsif i == 3
    redo
  end
  puts i
end

medium

A. puts should be before if statement

B. next cannot be used inside for loops

C. Syntax error: missing end for if

D. Using redo inside for loop causes infinite loop

Solution

1. Step 1: Analyze the use of redo in the loop

   The redo inside the elsif i == 3 causes the loop to repeat the same iteration infinitely because i does not change.

2. Step 2: Check other options for errors

   next works fine in for loops, the if statement is properly closed, and puts can be after if.

3. Final Answer:

   Using redo inside for loop causes infinite loop -> Option D

4. Quick Check:

   Redo repeats current step causing infinite loop [OK]

Hint: Redo without changing loop variable causes infinite loop [OK]

Common Mistakes:

• Thinking next is invalid in for loops
• Missing that redo repeats without increment
• Assuming syntax error due to indentation

5. You want to print numbers 1 to 5 but skip 3 and repeat printing 4 twice using next and redo. Which code achieves this correctly?

i = 0
while i < 5
  i += 1
  if i == 3
    # skip 3
  elsif i == 4
    # print 4 twice
  end
  puts i
end

hard

A. if i == 3
next
elsif i == 4
puts i
redo
next
end

B. if i == 3
next
elsif i == 4
redo
end

C. if i == 3
next
elsif i == 4
puts i
redo
end

D. if i == 3
redo
elsif i == 4
next
end

Solution

1. Step 1: Skip number 3 using next

   Using next when i == 3 skips printing 3 and moves to next iteration.

2. Step 2: Repeat printing 4 twice using redo

   When i == 4, print it once, then use redo to repeat the iteration and print 4 again.

3. Step 3: Verify code correctness

   if i == 3 next elsif i == 4 puts i redo end prints 4, then calls redo to repeat printing 4, and skips 3 correctly. Other options misuse next or redo causing errors or infinite loops.

4. Final Answer:

   if i == 3 next elsif i == 4 puts i redo end -> Option C

5. Quick Check:

   next skips, redo repeats current step [OK]

Hint: Use next to skip, redo after puts to repeat [OK]

Common Mistakes:

• Calling redo before puts causing infinite loop
• Using next after redo incorrectly
• Not skipping 3 properly