Adding custom attributes in Python - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a custom attribute color to the object car.

Python

class Car:
    pass

car = Car()
car.[1] = 'red'
print(car.color)

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

Aspeed

Byear

Ccolor

Dmodel

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong attribute name that doesn't match the print statement.

Trying to add attribute inside the class without defining __init__.

To add a custom attribute to an object, assign it using dot notation with the attribute name. Here, car.color = 'red' adds the color attribute.

2fill in blank

medium

Complete the code to add a custom attribute age with value 5 to the object dog.

Python

class Dog:
    pass

dog = Dog()
dog.[1] = 5
print(dog.age)

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

Aage

Bweight

Cbreed

Dname

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning the value to a wrong attribute name.

Forgetting to use dot notation.

Assigning dog.age = 5 adds the age attribute with value 5 to the dog object.

3fill in blank

hard

Fix the error in the code to add a custom attribute height with value 180 to the object person.

Python

class Person:
    pass

person = Person()
person[1] = 180
print(person.height)

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

A:height

B[height]

C['height']

D.height

Attempts:

3 left

💡 Hint

Common Mistakes

Using square brackets instead of dot notation.

Missing the dot before the attribute name.

To add an attribute, use dot notation like person.height = 180. Square brackets or other symbols cause errors.

4fill in blank

hard

Fill both blanks to add a custom attribute speed with value 100 to the object bike.

Python

class Bike:
    pass

bike = Bike()
bike[1] = [2]
print(bike.speed)

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

A.speed

B100

C50

D.distance

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong attribute names or values.

Forgetting the dot before the attribute name.

Use bike.speed = 100 to add the speed attribute with value 100.

5fill in blank

hard

Fill all three blanks to add a custom attribute name with value "Alice" to the object user.

Python

class User:
    pass

user = User()
user[1] = [2]
print(user.[3])

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

A.name

B"Alice"

Cname

D.username

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong attribute names or missing quotes around the string.

Mismatch between assigned attribute and printed attribute.

Assign user.name = "Alice" and print user.name to add and display the attribute.

Practice

1. What does adding a custom attribute to a Python object allow you to do?

easy

A. Delete the object from memory

B. Change the object's type permanently

C. Store extra information directly on that object

D. Prevent the object from being used in functions

Solution

1. Step 1: Understand what attributes are

   Attributes are values or properties stored inside an object to hold data or state.

2. Step 2: Adding custom attributes

   When you add a custom attribute, you attach new data directly to that object, allowing it to hold extra information.

3. Final Answer:

   Store extra information directly on that object -> Option C

4. Quick Check:

   Custom attributes = extra data on object [OK]

Hint: Custom attributes add new data fields to objects [OK]

Common Mistakes:

• Thinking attributes change the object's type
• Confusing attributes with deleting objects
• Believing attributes restrict object usage

2. Which of the following is the correct syntax to add a custom attribute color with value 'red' to an object car?

easy

A. car.color = 'red'

B. car['color'] = 'red'

C. car->color = 'red'

D. car.color('red')

Solution

1. Step 1: Identify attribute assignment syntax

   In Python, attributes are assigned using dot notation: object.attribute = value.

2. Step 2: Check each option

   car.color = 'red' uses dot notation correctly. car['color'] = 'red' uses dictionary syntax which is invalid for normal objects. car->color = 'red' uses arrow notation which is not Python syntax. car.color('red') tries to call attribute as a method, which is incorrect here.

3. Final Answer:

   car.color = 'red' -> Option A

4. Quick Check:

   Use dot notation to add attributes [OK]

Hint: Use dot notation: object.attribute = value [OK]

Common Mistakes:

• Using dictionary syntax on objects
• Using arrow (->) like in other languages
• Calling attribute as a function

3. What will be the output of this code?

class Dog:
    pass

my_dog = Dog()
my_dog.age = 5
print(my_dog.age)

medium

A. AttributeError

B. age

C. Dog

D. 5

Solution

1. Step 1: Understand attribute assignment

   The code creates an empty class Dog and an instance my_dog. Then it adds a custom attribute age with value 5 to my_dog.

2. Step 2: Print the attribute value

   Printing my_dog.age outputs the value stored, which is 5.

3. Final Answer:

   5 -> Option D

4. Quick Check:

   Custom attribute value prints correctly [OK]

Hint: Print attribute after assignment to see its value [OK]

Common Mistakes:

• Expecting class name or attribute name as output
• Thinking attribute does not exist yet
• Confusing attribute with method call

4. Find the error in this code that tries to add a custom attribute height to an object person:

class Person:
    def __init__(self, name):
        self.name = name

person = Person('Alice')
person.height = 170
print(person['height'])

medium

A. Missing height parameter in __init__

B. Using person['height'] instead of person.height

C. Cannot add attributes after object creation

D. Name attribute should be height

Solution

1. Step 1: Check how attribute is added

   The code correctly adds height using dot notation: person.height = 170.

2. Step 2: Identify incorrect attribute access

   Printing uses person['height'], which is dictionary syntax and invalid for normal objects. It should be person.height.

3. Final Answer:

   Using person['height'] instead of person.height -> Option B

4. Quick Check:

   Access attributes with dot, not brackets [OK]

Hint: Use dot notation to access attributes, not brackets [OK]

Common Mistakes:

• Using dictionary syntax on objects
• Thinking attributes must be in __init__
• Believing attributes can't be added later

5. You want to add a custom attribute status to multiple instances of a class Task only if their priority is above 5. Which code correctly does this?

hard

A. for t in tasks:
if t.priority > 5:
t.status = 'urgent'

B. for t in tasks:
t.status = 'urgent' if t.priority > 5 else None

C. for t in tasks:
if t.priority > 5:
t['status'] = 'urgent'

D. for t in tasks:
t.status = 'urgent'
if t.priority <= 5:
del t.status

Solution

1. Step 1: Understand the condition and attribute addition

   We want to add status only if priority > 5, so we check this condition inside the loop.

2. Step 2: Check each option's logic and syntax

   for t in tasks: if t.priority > 5: t.status = 'urgent' adds status only when priority > 5 using dot notation correctly. for t in tasks: t.status = 'urgent' if t.priority > 5 else None assigns status to None for others, which adds the attribute unnecessarily. for t in tasks: if t.priority > 5: t['status'] = 'urgent' uses dictionary syntax which is invalid. for t in tasks: t.status = 'urgent' if t.priority <= 5: del t.status adds status to all then deletes for low priority, which is inefficient and error-prone.

3. Final Answer:

   for t in tasks: if t.priority > 5: t.status = 'urgent' -> Option A

4. Quick Check:

   Use if condition and dot notation to add attributes selectively [OK]

Hint: Add attributes inside if-block with dot notation [OK]

Common Mistakes:

• Using dictionary syntax on objects
• Adding attribute to all instances regardless of condition
• Assigning None instead of skipping attribute