Python Coding challenge - Day 904| What is the output of the following Python Code?

 

Code Explanation:

1. Class Engine definition

class Engine:

Explanation

Declares a class named Engine.

A class is a blueprint for creating objects (here: engine objects).

2. start method inside Engine

    def start(self):

        return "Start"

Explanation

Defines an instance method start that takes self (the instance) as its only parameter.

When called on an Engine object it returns the string "Start".

Nothing else (no print) — it just returns the value.

3. Class Car definition

class Car:

Explanation

Declares a class named Car.

This class will represent a car and, as we’ll see, it will contain an Engine object (composition / “has-a” relationship).

4. __init__ constructor of Car

    def __init__(self):

        self.e = Engine()

Explanation

__init__ is the constructor — it runs when a Car object is created.

self.e = Engine() creates a new Engine instance and assigns it to the instance attribute e.

So every Car object gets its own Engine object accessible as car_instance.e.

5. Creating a Car object

c = Car()

Explanation

Instantiates a Car object and stores it in variable c.

During creation, Car.__init__ runs and c.e becomes an Engine instance.

6. Calling the engine start method and printing result

print(c.e.start())

Explanation

c.e accesses the Engine instance stored in the Car object c.

c.e.start() calls the start method on that Engine instance; it returns the string "Start".

print(...) prints the returned string to the console.

Final Output

Start

600 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 903| What is the output of the following Python Code?

 

Code Explanation:

1. Class Definition

class Calc:

Explanation:

A class named Calc is created.

It will contain a method that behaves differently depending on the number of arguments passed.

2. Method Definition With Default Values

def process(self, x=None, y=None):

Explanation:

The method process() accepts two optional parameters: x and y.

If no values are passed, they are automatically None.

This allows the method to act like an overloaded function in Python.

3. First Condition: Both x and y Present

if x and y:

    return x * y

Explanation:

This runs only when both x and y have values (not None or 0).

In that case, the method returns the product of the two numbers.

4. Second Condition: Only x Present

elif x:

    return x ** 2

Explanation:

This runs when only x has a value and y is None.

It returns the square of x (x × x).

5. Default Case: No Valid Input

return "Missing"

Explanation:

If neither x nor y is provided (or both are falsy), the method returns "Missing".

6. First Function Call
Calc().process(4)

What happens?

x = 4

y = None

First condition: if x and y → False (because y is None)

Second condition: elif x → True

→ returns 4 ** 2 = 16

7. Second Function Call

Calc().process(4, 3)

What happens?

x = 4

y = 3

First condition: if x and y → True

→ returns 4 * 3 = 12

8. Final Print Output

print(Calc().process(4), Calc().process(4, 3))

Output:

First result → 16

Second result → 12

FINAL OUTPUT

16 12

700 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 902| What is the output of the following Python Code?

 

Code Explanation: 

1. Class Definition

class Test:

Explanation:

A class named Test is created.

It contains a method show() that behaves differently depending on how many arguments are passed.

This is an example of method overloading-like behavior in Python.

2. Method Definition With Default Parameters

def show(self, a=None, b=None):

Explanation:

The method show() takes two optional parameters: a and b.

a=None and b=None mean that unless values are given, they automatically become None.

3. First Condition

if a and b:

    return a + b

Explanation:

This runs when both a and b have truthy (non-zero/non-None) values.

It returns a + b.

4. Second Condition

elif a:

    return a

Explanation:

This runs when only a is truthy.

It returns just a.

5. Default Return

return "No Value"

Explanation:

If neither a nor b are given, the method returns the string "No Value".

6. First Function Call

Test().show(5)

Explanation:

Here, a = 5, b = None

Condition check:

if a and b → False (b is None)

elif a → True

So it returns 5.

7. Second Function Call

Test().show(5, 10)

Explanation:

Here, a = 5, b = 10

Condition check:

if a and b → True

So it returns 5 + 10 = 15.

8. Final Print Statement

print(Test().show(5), Test().show(5, 10))

Explanation:

First call prints 5

Second call prints 15

Final Output

5 15

400 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 901| What is the output of the following Python Code?

 

Code Explanation:

1. Class Definition

class Player:

    score = 5

Explanation:

A class named Player is created.

score = 5 is a class variable.

Class variables belong to the class itself, not to individual objects.

All objects will share the same class variable unless overridden by instance variable.

2. Creating First Object

p1 = Player()

Explanation:

An object p1 of class Player is created.

p1 does not have its own score, so it will use the class variable score = 5.

3. Changing Class Variable Directly Using Class Name

Player.score = 20

Explanation:

This line updates the class variable.

Now the class variable score becomes 20.

Every object that does not have its own score variable will see 20.

4. Creating Second Object

p2 = Player()

Explanation:

Another object p2 is created.

Since class variable score was updated to 20,

p2.score will be 20.

5. Print Values

print(p1.score, p2.score)

Explanation:

p1.score

p1 does not have its own score

uses class variable → 20

p2.score

same logic → 20

Final Output

20 20

500 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 900| What is the output of the following Python Code?

 

Code Explanation:

1. Class Definition

class A:

Explanation:

Defines a class named A.

2. Class Variable

x = 10

Explanation:

This is a class variable.

It belongs to the class, not to any specific object.

It can be accessed using:

A.x

obj.x

3. Method Definition

def show(self):

Explanation:

show is an instance method.

self refers to the current object.

x = 20

Explanation:

This creates a local variable x inside the show() method.

This does NOT change:

the class variable x

or the object variable

This x = 20 exists only inside this method.

4. Object Creation

obj = A()

Explanation:

Creates an object obj of class A.

No instance variable x is created here.

The class variable x = 10 still exists.

5. Method Call

obj.show()

Explanation:

Calls the show() method.

Inside show():

x = 20 is created as a local variable

It is destroyed after the method finishes

It does NOT affect obj.x or A.x.

6. Print Statement

print(obj.x)

Explanation:

Since obj has no instance variable x, Python looks for:

Instance variable 

Class variable 

It finds:

A.x = 10

So it prints 10.

Final Output

10

400 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 899| What is the output of the following Python Code?

 Code Explanation:

1. Class Definition

class Test:

Explanation:

This line defines a class named Test.

A class is a blueprint used to create objects.

2. Constructor Method (__init__)

def __init__(self, x):

Explanation:

__init__ is a special constructor method.

It is called automatically when a new object is created.

self refers to the current object.

x is a parameter passed while creating the object.

self.x = x

Explanation:

This line stores the value of x inside the object.

It creates an instance variable named x.

3. Operator Overloading Method (__add__)

def __add__(self, other):

Explanation:

__add__ is a special method used for operator overloading.

It allows us to use the + operator with class objects.

self → first object

other → second object

return self.x + other.x

Explanation:

This adds:

self.x → value from first object

other.x → value from second object

It returns the sum of the two values.

4. Object Creation

obj1 = Test(5)

Explanation:

Creates an object obj1.

Calls the constructor: self.x = 5

So, obj1.x = 5

obj2 = Test(10)

Explanation:

Creates another object obj2.

Calls the constructor: self.x = 10

So, obj2.x = 10

5. Addition Operation

print(obj1 + obj2)

Explanation:

obj1 + obj2 automatically calls:

obj1.__add__(obj2)

Which returns:

5 + 10 = 15

Final Output

15

500 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 898| What is the output of the following Python Code?

 

Code Explanation:

1. Defining the Class

class Box:

This line defines a class named Box.

A class acts as a template for creating objects.

2. Creating the Constructor Method

def __init__(self, n):

This is the constructor method.

It runs automatically when a new object is created.

self → Refers to the current object

n → A value passed while creating the object

3. Initializing an Instance Variable

self.n = n

This creates an instance variable n.

The value passed during object creation is stored in self.n.

After this:

self.n → 5

4. Defining the __repr__ Method

def __repr__(self):

__repr__ is a special method in Python.

It defines how an object should be displayed when printed.

5. Returning a Formatted String

return f"Box({self.n})"

This returns a formatted string representation of the object.

self.n is inserted into the string using an f-string.

This means:

repr(b) → "Box(5)"

6. Creating an Object

b = Box(5)

This creates an object b of the class Box.

The value 5 is passed to the constructor and stored in b.n.

7. Printing the Object

print(b)

When print(b) is executed, Python automatically calls:

b.__repr__()

Which returns:

"Box(5)"

So the final output is:

Box(5)

Final Output

Box(5)

700 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 897| What is the output of the following Python Code?

 

Code Explanation:

1. Defining a Class

class User:

This line defines a class named User.

A class is like a blueprint for creating objects.

2. Creating the Constructor Method

def __init__(self, name):

This is a constructor method.

It runs automatically when a new object is created from the class.

self → Refers to the current object.

 name → A parameter used to pass the user's name.

3. Initializing an Attribute

self.name = name

This line creates an instance variable called name.

It stores the value passed during object creation.

4. Creating an Object of the Class

u = User("Sam")

This creates an object u of the User class.

"Sam" is passed to the constructor and stored in u.name.

Now:

u.name → "Sam"

5. Adding a New Attribute Dynamically

u.score = 90

This adds a new attribute score to the object u.

Python allows adding new attributes to objects outside the class.

Now:

u.score → 90

6. Printing the Attribute Value

print(u.score)

This prints the value of the score attribute.

Output will be:

90

Final Output

90

400 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 892| What is the output of the following Python Code?

 

Code Explanation:

1. Class Definition

class Num:

This defines a class named Num.

It is a blueprint for creating objects that store a number.

2. Constructor Method

    def __init__(self, x):

        self.x = x

__init__ is the constructor that runs when an object is created.

x is the value passed while creating the object.

self.x = x stores the value inside the object.

3. Operator Overloading for /

    def __truediv__(self, other):

        return Num(self.x * other.x)

__truediv__ is a magic method that overloads the / operator.

Instead of performing division, this method performs multiplication.

self.x * other.x multiplies the values.

A new Num object is returned with the multiplied value.

4. Creating First Object

n1 = Num(2)

Creates an object n1.

self.x = 2 is stored in n1.

5. Creating Second Object

n2 = Num(6)

Creates another object n2.

self.x = 6 is stored in n2.

6. Using the / Operator

print((n1 / n2).x)

n1 / n2 calls the __truediv__ method.

Inside the method:

self.x * other.x = 2 * 6 = 12

A new Num(12) object is created.

.x extracts the value 12.

print() displays:

12

Final Output

12

400 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 891| What is the output of the following Python Code?

 

Code Explanation:

1. Defining the Class

class Data:

This creates a new class named Data.

A class is a blueprint for creating objects (instances) that can hold data and behavior.

2. Defining the Constructor (__init__)

    def __init__(self, v):

        self.v = v

__init__ is the constructor method. It runs automatically when you create a new Data object.

Parameter v is the value passed while creating the object.

self.v = v stores that value in an instance attribute named v.

So each Data object will have its own v.

3. Defining __repr__ (Representation Method)

    def __repr__(self):

        return f"Value={self.v}"

__repr__ is a magic (dunder) method that defines how the object is represented as a string, mainly for debugging or interactive console.

When you do print(d) or just type d in a Python shell, Python calls __repr__ (if __str__ isn’t defined).

It returns a formatted string:

f"Value={self.v}" → uses f-string to embed the value of self.v.

For example, if self.v = 9, it returns "Value=9".

4. Creating an Object

d = Data(9)

This creates an instance d of the Data class.

__init__ is called with v = 9.

Inside __init__, self.v is set to 9.

So now d.v == 9.

5. Printing the Object

print(d)

When you pass d to print(), Python looks for:

First: __str__ method (not defined here)

Then: __repr__ method (defined!)

So it calls d.__repr__(), which returns "Value=9".

print outputs:

Value=9

Final Output

Value=9

700 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 894| What is the output of the following Python Code?

 

Code Explanation:

Class Definition

class Product:

This defines a new class named Product.

The class will represent a product that has a price and some logic around it.

Constructor (__init__) Method

    def __init__(self, p):

        self._price = p

__init__ is the constructor — it runs automatically when you create a new Product object.

It takes one argument besides self: p, which represents the base price.

self._price = p:

Stores the value of p in an attribute called _price.

The single underscore _price is a convention meaning “internal use” (protected-style attribute).

Property Decorator

    @property

    def price(self):

        return self._price * 2

@property turns the price method into a read-only attribute.

That means you can access price like p.price instead of p.price().

Inside the method:

return self._price * 2

It doesn’t return the raw _price.

Instead, it returns double the stored price.

This is a form of encapsulation + computed property:

the internal value is _price, but the external visible value is _price * 2.

Creating an Object

p = Product(40)

Creates an instance p of the Product class.

Calls __init__(self, p) with p = 40.

Inside __init__, _price becomes 40.

So now: p._price == 40.

Accessing the Property

print(p.price)

Accessing p.price triggers the @property method price().

It calculates: self._price * 2 → 40 * 2 = 80.

print outputs:

80

Final Output

80

500 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 893| What is the output of the following Python Code?

 

Code Explanation:

1. Defining Class A

class A:

This line defines a new class named A.

A class is a blueprint used to create objects.

2. Defining Method in Class A

    def val(self):

        return 4

val() is an instance method of class A.

self refers to the current object.

This method simply returns the value 4.

3. Defining Class B (Inheritance)

class B(A):

This defines a new class B.

B(A) means B inherits from A.

So, class B has access to methods of class A.

4. Overriding Method in Class B

    def val(self):

Class B overrides the val() method of class A.

This means B provides its own version of the method.

5. Calling Parent Method Using super()

        return super().val() + 6

super().val() calls the parent class (A) method val().

A.val() returns 4.

Then + 6 is added:

4 + 6 = 10

So this method returns 10.

6. Creating Object and Printing Output

print(B().val())

B() creates an object of class B.

.val() calls the overridden method in class B.

The method returns 10.

print() displays:

10

Final Output

10

400 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 896| What is the output of the following Python Code?

 

Code Explanation:

1. Class Definition

class A:

This defines a class named A.

A class is a blueprint for creating objects.

Any object created from this class will follow its structure.

2. Constructor Method

    def __init__(self):

__init__ is the constructor.

It runs automatically when an object is created.

It is used to initialize object data.

3. Private Variable Creation

        self.__x = 5

__x is a private variable.

Python performs name mangling, converting:

__x → _A__x

This prevents direct access from outside the class.

The value 5 is safely stored inside the object.

4. Object Creation

a = A()

An object named a is created.

The constructor runs automatically.

Now internally the object contains:

a._A__x = 5

5. Checking Attribute Using hasattr()

print(hasattr(a, "__x"))

hasattr(object, "attribute") checks if the attribute exists.

Since __x was name-mangled to _A__x,

the exact name "__x" does not exist in the object.

So this returns:

False

Final Output

False

300 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 895| What is the output of the following Python Code?

 

Code Explanation:1. Class Definition

class Info:

This line defines a new class named Info.

A class is a blueprint for creating objects.

Objects created from this class will store a value and display it in a custom format.

2. Constructor Method

    def __init__(self, n):

        self.n = n

__init__ is the constructor method.

It runs automatically when a new object is created.

n is the value passed while creating the object.

self.n = n stores that value inside the object as an instance variable.

3. __repr__ Magic Method

    def __repr__(self):

        return f"Info[{self.n}]"

__repr__ is a special (magic) method used to define how the object looks when printed.

It returns a formatted string showing the value of n.

So if n = 11, it will return:

Info[11]

4. Object Creation

i = Info(11)

This creates an object i of the Info class.

The constructor assigns:

i.n = 11

5. Printing the Object

print(i)

print(i) automatically calls the __repr__ method.

It prints the formatted string returned by __repr__.

Final Output

Info[11]

400 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 890| What is the output of the following Python Code?

 

Code Explanation:

Defining Class A

class A:

This creates a class named A.

It will act as a base (parent) class.

Method Inside Class A

    def get(self):

        return "A"

Defines a method get inside class A.

When get() is called on an object of class A, it will return the string "A".

Defining Class B That Inherits from A

class B(A):

Creates a new class B that inherits from A.

That means B automatically gets all methods and attributes of A (unless overridden).

Overriding get in Class B

    def get(self):

        return "B"

Class B defines its own version of the get method.

This overrides the get method from class A.

Now, when get() is called on a B object, it returns "B" instead of "A".

Defining Class C That Inherits from B

class C(B):

    pass

Class C is defined and it inherits from B.

The pass statement means no new methods or attributes are added in C.

So C simply uses whatever it gets from B (and indirectly from A).

Creating an Object of C and Calling get

print(C().get())

C() creates a new object of class C.

.get() calls the get method on that object.

Python looks for get method in this order (MRO):

First in C → none

Then in B → found def get(self): return "B"

So it uses B’s version of get, which returns "B".

Final printed output:

B

Final Answer:

B

700 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 889| What is the output of the following Python Code?

 

Code Explanation:

1. Defining the Class

class User:

This defines a new class called User.

A class is a blueprint for creating objects (instances).

Objects of User will represent users with some attributes (like name, age, etc.).

2. Constructor Method (__init__)

    def __init__(self, name):

        self.name = name

__init__ is the constructor method.

It runs automatically when you create a new User object.

It takes one parameter besides self: name.

self.name = name creates an instance attribute name and assigns it the value passed when creating the object.

After this, every User object will have its own name.

3. Creating an Object of User

u = User("Tom")

This line creates an object u of class User.

It calls the constructor: __init__(u, "Tom").

Inside __init__, self.name becomes "Tom".

So now:

u.name == "Tom"

4. Adding a New Attribute Dynamically

u.age = 18

Here, you are adding a new attribute age to the object u outside the class definition.

Python allows dynamic attributes, so you don’t need to declare all attributes inside __init__.

Now u has:

u.name = "Tom"

u.age = 18

5. Printing the age Attribute

print(u.age)

This accesses the age attribute of object u.

Since you set u.age = 18 earlier, this prints:

18

Final Output

18

100 Python Programs for Beginner with explanation

Read More

Python Coding challenge - Day 888| What is the output of the following Python Code?

 

Code Explanation:

1. Class Definition

class Item:

This defines a new class called Item.

Classes are blueprints for objects, which can have attributes and methods.

2. Constructor Method

    def __init__(self, p):

        self._price = p

__init__ is the constructor, called automatically when a new object is created.

p is passed as a parameter when creating the object.

self._price = p stores the price in a protected attribute _price.

By convention, a single underscore _ indicates that this attribute should not be accessed directly outside the class.

3. Property Decorator

    @property

    def price(self):

        return self._price + 20

@property turns the price() method into a read-only attribute.

When you access i.price, it automatically calls this method.

The method returns _price plus 20, effectively adding a fixed markup to the price.

Benefit: You can compute or validate values dynamically while keeping a clean attribute-like access.

4. Creating an Object

i = Item(80)

Creates an object i of the class Item with _price = 80.

The constructor initializes the protected attribute _price.

5. Accessing the Property

print(i.price)

Accessing i.price calls the price property method.

The method calculates _price + 20 = 80 + 20 = 100.

print outputs:

100

Final Output:

100

400 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 887| What is the output of the following Python Code?

 Code Explanation:

1. Class Definition

class Counter:

This defines a new class named Counter.

A class is a blueprint for creating objects, and can contain class variables, instance variables, and methods.

2. Class Variable

    count = 0

count is a class variable, shared among all instances of the class.

Every object of Counter accesses the same count.

Initially, count is set to 0.

3. Class Method Definition

    @classmethod

    def increment(cls):

@classmethod decorator defines a class method.

cls refers to the class itself (not an instance).

Class methods can access and modify class variables.

4. Modifying the Class Variable

        cls.count += 3

Inside the class method, cls.count accesses the shared class variable count.

It increments count by 3 each time the method is called.

Changes affect all objects of the class because count is shared.

5. Calling Class Method

Counter.increment()

Counter.increment()

The class method increment is called twice using the class name.

First call: count = 0 + 3 = 3

Second call: count = 3 + 3 = 6

6. Printing the Class Variable

print(Counter.count)

Accessing Counter.count prints the current value of the class variable count.

Output:

6

500 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 886| What is the output of the following Python Code?

 

Code Explanation:

1. Class Definition

class Data:

You define a class named Data.

A class is a blueprint for creating objects that can hold data and behavior.

2. Constructor (__init__)

    def __init__(self, v):

        self.v = v

__init__ is the constructor that runs when a new Data object is created.

It accepts a parameter v and assigns it to the instance attribute self.v.

After this, every Data instance stores its value in v.

3. __repr__ Magic Method

    def __repr__(self):

        return f"<<{self.v}>>"

__repr__ is a special (magic) method that returns the “official” string representation of the object.

When you inspect the object in the REPL or use print() (if __str__ is not defined), Python will use __repr__.

This implementation returns a formatted string <<value>>, inserting the instance’s v value into the template.

4. Creating an Instance

d = Data(8)

This creates an instance d of class Data with v = 8.

The constructor stores 8 in d.v.

5. Printing the Object

print(d)

print(d) tries to convert d to a string. Because Data defines __repr__ (and no __str__), Python uses __repr__.

The __repr__ method returns the string "<<8>>", which print outputs.

Final Output

<<8>>

500 Days Python Coding Challenges with Explanation

Read More

Python Coding challenge - Day 885| What is the output of the following Python Code?

 

Code Explanation:

1. Class Definition

class Box:

Defines a new class named Box — a blueprint for creating Box objects that will hold a value n and expose a computed property.

2. Constructor

    def __init__(self, n):

        self._n = n

__init__ is the constructor; it runs when you create a Box instance.

The parameter n is passed in when constructing the object.

self._n = n stores n in the instance attribute _n. By convention the single underscore (_n) signals a “protected” attribute (meant for internal use), but it is still accessible from outside.

3. Property Definition

    @property

    def triple(self):

        return self._n * 3

@property turns the triple() method into a read-only attribute called triple.

When you access b.triple, Python calls this method behind the scenes.

return self._n * 3 computes and returns three times the stored value _n. This does not change _n — it only computes a value based on it.

4. Creating an Instance

b = Box(6)

Creates a Box object named b, passing 6 to the constructor.

Inside __init__, self._n is set to 6.

5. Accessing the Property and Printing

print(b.triple)

Accessing b.triple invokes the triple property method, which computes 6 * 3 = 18.

print outputs the returned value.

Final Output

18

400 Days Python Coding Challenges with Explanation

Read More