DRY (Don't Repeat Yourself) in Software Engineering - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to follow the DRY principle by avoiding repeated print statements.

Software Engineering

def greet(name):
    print(f"Hello, {name}!")

# Instead of repeating print, call [1]

Drag options to blanks, or click blank then click option'

Agreet

Bprint

Chello

Drepeat

Attempts:

3 left

💡 Hint

Common Mistakes

Using print directly instead of calling the function.

Using a function like greet avoids repeating the print statement multiple times, following DRY.

2fill in blank

medium

Complete the sentence to explain the DRY principle.

Software Engineering

"DRY means you should avoid [1] code."

Drag options to blanks, or click blank then click option'

Arepeating

Bdeleting

Cwriting

Dcommenting

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing 'writing' which is too general.

DRY stands for "Don't Repeat Yourself," so it means avoiding repeating code.

3fill in blank

hard

Fix the error in the code to avoid repeating the calculation.

Software Engineering

def area(radius):
    return 3.14 * radius [1] 2

# Use the function instead of repeating the formula

Drag options to blanks, or click blank then click option'

A+

B*

C**

D//

Attempts:

3 left

💡 Hint

Common Mistakes

Using '*' which multiplies but is less clear than '**' for square.

The exponent operator ** correctly calculates radius squared, avoiding repeating the multiplication.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that avoids repeating the length calculation.

Software Engineering

lengths = {word: [1] for word in words if len(word) [2] 3}

Drag options to blanks, or click blank then click option'

Alen(word)

B>

C<

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'word' instead of 'len(word)' for the value.

Using len(word) avoids repeating length calculation, and > filters words longer than 3.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that avoids repeating keys and filters positive values.

Software Engineering

result = { [1]: [2] for [1], [2] in data if [2] [3] 0 }

Drag options to blanks, or click blank then click option'

Ak

Bv

C>

Ditem

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'item' which is not standard for keys or values.

Using k and v avoids repeating key and value names, and > filters positive values.

Practice

1. What does the DRY principle in software engineering mean?

easy

A. Don't Repeat Yourself - avoid writing the same code multiple times

B. Debug Regularly Yourself - test code often

C. Develop Rapidly Yesterday - finish tasks quickly

D. Design Reusable Yields - focus on output

Solution

1. Step 1: Understand the acronym DRY

   DRY stands for "Don't Repeat Yourself" which means avoiding duplicate code.

2. Step 2: Match the meaning to options

   Don't Repeat Yourself - avoid writing the same code multiple times correctly explains DRY as avoiding repeated code to keep it clean and maintainable.

3. Final Answer:

   Don't Repeat Yourself - avoid writing the same code multiple times -> Option A

4. Quick Check:

   DRY = Don't Repeat Yourself [OK]

Hint: DRY means write code once, reuse it everywhere [OK]

Common Mistakes:

• Confusing DRY with debugging or speed
• Thinking DRY means writing less code overall
• Assuming DRY is about output or design only

2. Which of the following is the correct way to apply DRY in code?

easy

A. Use functions or methods to reuse code

B. Copy and paste the same code block multiple times

C. Write all code in one long script without breaks

D. Repeat variable declarations for clarity

Solution

1. Step 1: Identify how to avoid code repetition

   Functions or methods allow reusing code by calling them multiple times instead of copying code.

2. Step 2: Compare options for DRY compliance

   Use functions or methods to reuse code uses functions to reuse code, which follows DRY. Others increase repetition.

3. Final Answer:

   Use functions or methods to reuse code -> Option A

4. Quick Check:

   Functions help reuse code [OK]

Hint: Functions help avoid repeating code [OK]

Common Mistakes:

• Copy-pasting code instead of using functions
• Writing long scripts without modular parts
• Repeating declarations unnecessarily

3. Consider this code snippet:

def greet():
    print('Hello!')

greet()
greet()

What is the main benefit of using the function greet() here?

medium

A. It causes a syntax error

B. It repeats the print statement twice

C. It makes the program slower

D. It avoids repeating the print code by calling the function

Solution

1. Step 1: Analyze the function usage

   The function greet() contains the print statement and is called twice.

2. Step 2: Understand the benefit

   Instead of writing print('Hello!') twice, the function is called twice, avoiding code repetition.

3. Final Answer:

   It avoids repeating the print code by calling the function -> Option D

4. Quick Check:

   Function calls reuse code [OK]

Hint: Functions let you write code once, run many times [OK]

Common Mistakes:

• Thinking function calls duplicate code
• Assuming functions slow down simple prints
• Believing this causes syntax errors

4. Identify the problem in this code snippet related to DRY:

def calculate_area(radius):
    area = 3.14 * radius * radius
    return area

print(calculate_area(5))
print(3.14 * 7 * 7)

medium

A. The value of pi is incorrect

B. The function is not called for the second print, repeating code

C. The function has a syntax error

D. The function returns nothing

Solution

1. Step 1: Check code repetition

   The first print uses the function, but the second print repeats the area calculation manually.

2. Step 2: Identify DRY violation

   Repeating the formula outside the function breaks DRY; both should use the function.

3. Final Answer:

   The function is not called for the second print, repeating code -> Option B

4. Quick Check:

   Repeated formula outside function breaks DRY [OK]

Hint: Always reuse functions instead of repeating formulas [OK]

Common Mistakes:

• Ignoring repeated formula outside function
• Thinking the function has syntax errors
• Assuming pi value causes DRY issues

5. You have a list of prices and want to apply a 10% discount to each without repeating code. Which approach best follows the DRY principle?

hard

A. Write a loop that calculates discounted price inside the loop body each time

B. Manually calculate discount for each price separately

C. Create a function to calculate discount and call it for each price

D. Copy the discount calculation code multiple times in the program

Solution

1. Step 1: Understand the task

   Applying the same discount calculation repeatedly should be done without copying code.

2. Step 2: Choose the DRY-compliant method

   Creating a function for discount calculation and calling it for each price avoids repetition and keeps code clean.

3. Final Answer:

   Create a function to calculate discount and call it for each price -> Option C

4. Quick Check:

   Functions prevent repeated discount code [OK]

Hint: Use functions to apply repeated calculations [OK]

Common Mistakes:

• Repeating calculation code in loops or manually
• Copy-pasting discount logic multiple times
• Not using reusable code blocks