Python Coding challenge - Day 1137| What is the output of the following Python Code?

 

Code Explanation:

🔹 1. Initializing the List

funcs = []

An empty list funcs is created

This list will store functions

🔹 2. Starting the Loop

for i in range(3):

Loop runs 3 times with values:

i = 0, 1, 2

🔹 3. Defining the Function Inside Loop

def f():

    return i

A function f is defined in each iteration

⚠️ Important: The function does not store the current value of i immediately

Instead, it refers to i (late binding)

👉 This means:

All functions will look up i when they are called, not when they are created

🔹 4. Appending Function to List

funcs.append(f)

The function f is added to the list

After loop ends, funcs contains 3 functions

🔹 5. After Loop Ends

Final value of i is:

i = 2

All functions refer to this same i

🔹 6. Calling the Functions

print([f() for f in funcs])

Each function is called one by one

Each function returns the current value of i, which is 2

🔹 ✅ Final Output

[2, 2, 2]

Book: 900 Days Python Coding Challenges with Explanation

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Python Coding challenge - Day 1136| What is the output of the following Python Code?

 

Code Explanation:

🔹 1. Metaclass Definition

class Meta(type):

    def __new__(cls, name, bases, dct):

        dct['x'] = 100

        return super().__new__(cls, name, bases, dct)

Meta is a metaclass (inherits from type)

__new__ runs when a class is being created, not an object

It receives the class attributes in dct

It modifies the class dictionary by setting:

x = 100

🔹 2. Class Creation (A)

class A(metaclass=Meta):

    x = 10

Python sends this class definition to the metaclass

Internally:

Meta.__new__(Meta, 'A', (), {'x': 10})

The metaclass changes:

{'x': 10} → {'x': 100}

🔹 3. Final Class Structure

After metaclass processing, class A becomes:

class A:

    x = 100

The original x = 10 is overwritten

🔹 4. Object Creation

obj = A()

Creates an instance of class A

obj itself has no x attribute

🔹 5. Attribute Lookup

print(obj.x)

Python checks:

obj → not found

class A → finds x = 100

🔹 ✅ Final Output

100

Book:  500 Days Python Coding Challenges with Explanation

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🚀 Day 38/150 – Prime Number Check in Python

A Prime Number is a number greater than 1 that has only two factors: 1 and itself.

Examples:
2, 3, 5, 7, 11 → Prime Numbers
4, 6, 8, 9 → Not Prime Numbers

Let’s explore different ways to check prime number in Python 👇

🔹 Method 1 – Using for Loop

n = 7 is_prime = True if n <= 1: is_prime = False else: for i in range(2, n): if n % i == 0: is_prime = False break print("Prime Number" if is_prime else "Not Prime Number")

Simple beginner-friendly method.

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🔹 Method 2 – Taking User Input

n = int(input("Enter a number: "))
is_prime = True

if n <= 1:
    is_prime = False
else:
    for i in range(2, n):
        if n % i == 0:
            is_prime = False
            break

print("Prime Number" if is_prime else "Not Prime Number")

Useful when you want to test different numbers.

🔹 Method 3 – Optimized Using √n

n = 29
is_prime = True

if n <= 1:
    is_prime = False
else:
    for i in range(2, int(n ** 0.5) + 1):
        if n % i == 0:
            is_prime = False
            break

print("Prime Number" if is_prime else "Not Prime Number")

 More efficient because factors repeat after the square root.

🔹 Method 4 – Using while Loop

n = 13 i = 2 is_prime = True if n <= 1: is_prime = False else: while i < n: if n % i == 0: is_prime = False break i += 1 print("Prime Number" if is_prime else "Not Prime Number")

Same logic, just using a different loop.

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💡 Key Takeaways

1)Prime numbers have exactly two factors
2)Numbers less than or equal to 1 are not prime
3)Checking up to √n is faster than checking all numbers
4)The optimized method is better for larger values

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🚀 Day 39/150 – Print Prime Numbers in a Range in Python

 

🚀 Day 39/150 – Print Prime Numbers in a Range in Python

Prime numbers are numbers greater than 1 that have only two factors: 1 and itself.

Examples:

2, 3, 5, 7, 11, 13...

Let’s explore different ways to print prime numbers in a given range using Python 👇

🔹 Method 1 – Using for Loop

start = 1
end = 20

for num in range(start, end + 1):
    if num > 1:
        for i in range(2, num):
            if num % i == 0:
                break
        else:
            print(num, end=" ")

✅ Simple beginner-friendly method.

🔹 Method 2 – Taking User Input

start = int(input("Enter start: ")) end = int(input("Enter end: ")) for num in range(start, end + 1): if num > 1: for i in range(2, num): if num % i == 0: break else: print(num, end=" ")

✅ Useful for dynamic programs.

🔹 Method 3 – Optimized Using √n

start = 1
end = 50

for num in range(start, end + 1):
    if num > 1:
        is_prime = True

        for i in range(2, int(num ** 0.5) + 1):
            if num % i == 0:
                is_prime = False
                break

        if is_prime:
            print(num, end=" ")

✅ Faster for larger ranges.

🔹 Method 4 – Using Function
def is_prime(n):
    if n <= 1:
        return False

    for i in range(2, int(n ** 0.5) + 1):
        if n % i == 0:
            return False

    return True


for num in range(1, 21):
    if is_prime(num):
        print(num, end=" ")







✅ Clean and reusable.

🎯 Output

2 3 5 7 11 13 17 19


🔑 Key Takeaways

Prime numbers are greater than 1.

Use nested loops to test each number.

Check till √n for optimization.

Functions make code reusable.

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Python Coding Challenge - Question with Answer (ID -030526)

 

Explanation:

🔹 Line 1: Creating the List

x = [1, 2, 3]

A list named x is created.

It contains three elements:

Index 0 → 1

Index 1 → 2

Index 2 → 3

🔹 Line 2: The Print Statement

print(x.pop(1) + x[1])

Let’s break this into parts:

🔸 Step 1: x.pop(1)

The pop(1) function:

Removes the element at index 1

Returns the removed value

👉 Before pop: x = [1, 2, 3]

👉 After pop: x = [1, 3]

👉 Returned value: 2

🔸 Step 2: x[1]

Now the updated list is [1, 3]

x[1] refers to the element at index 1

👉 x[1] = 3

🔸 Step 3: Addition

2 + 3 = 5

🔹 Final Output

5

Book: Python for GIS & Spatial Intelligence

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🚀 Day 37/150 – Multiplication Table in Python

A multiplication table shows the result of multiplying a number with a series of numbers.

Example for 5:

5 x 1 = 5

5 x 2 = 10

5 x 3 = 15

Let’s explore different ways to print multiplication table in Python 👇

🔹 Method 1 – Using for Loop

n = 5

for i in range(1, 11):
    print(n, "x", i, "=", n * i)

✅ Most common and easiest method.

🔹 Method 2 – Taking User Input

n = int(input("Enter a number: "))

for i in range(1, 11):
    print(n, "x", i, "=", n * i)

✅ Useful for dynamic tables.

🔹 Method 3 – Using while Loop

n = 5
i = 1

while i <= 10:
    print(n, "x", i, "=", n * i)
    i += 1

✅ Good for loop practice.

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🔹 Method 4 – Using List Comprehension

n = 5

table = [n * i for i in range(1, 11)]
print(table)

✅ Creates values as a list.

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🔹 Method 5 – Using Function

def table(n):
    for i in range(1, 11):
        print(f"{n} x {i} = {n * i}")

table(5)

✅ Reusable and clean method.

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🎯 Output

5 x 1 = 5
5 x 2 = 10
5 x 3 = 15
...
5 x 10 = 50

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🔑 Key Takeaways

• Use for loop for fixed repetitions.
• Use while loop for manual control.
• f-strings make output cleaner.
• Functions help reuse code.

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🔥 Follow for Day 38/150 – Prime Number Check in Python

100 Python Projects — From Beginner to Expert

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