🚀 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.

---

🔹 Method 4 – Using List Comprehension

n = 5

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

✅ Creates values as a list.

---

🔹 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.

---

🎯 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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Python Coding Challenge - Question with Answer (ID -020526)

 

Explanation:

🔹 Step 1: Understand Operator Priority

and has higher priority than or

👉 So expression becomes:

0 or [] or (5 and 6)

🔹 Step 2: Evaluate (5 and 6)

5 and 6

5 → Truthy ✅

So and returns second value

👉 Result:

6

🔹 Step 3: Now Expression Becomes

0 or [] or 6

🔹 Step 4: Evaluate or (Left to Right)

👉 First value:

0

0 → Falsy ❌ → move ahead

👉 Second value:

[]

Empty list → Falsy ❌ → move ahead

👉 Third value:

6

6 → Truthy ✅

👉 or returns first truthy value

🔹 Step 5: Final Result

6

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🚀 Day 36/150 – Sum of Digits of a Number in Python

🚀 Day 36/150 – Sum of Digits of a Number in Python

The sum of digits means adding all digits of a number.

Examples:
1234 → 1 + 2 + 3 + 4 = 10
507 → 5 + 0 + 7 = 12

Let’s explore different ways to find sum of digits in Python 👇

🔹 Method 1 – Using while Loop

n = 1234 total = 0 while n > 0: digit = n % 10 total += digit n //= 10 print("Sum of digits:", total)

✅ Best method for logic building.

🔹 Method 2 – Taking User Input

n = int(input("Enter a number: "))
total = 0

temp = abs(n)

while temp > 0:
    total += temp % 10
    temp //= 10

print("Sum of digits:", total)

✅ Works for negative numbers too.

🔹 Method 3 – Using String + sum()

n = 1234 total = sum(int(i) for i in str(abs(n))) print("Sum of digits:", total)

✅ Shortest and cleanest method.

🔹 Method 4 – Using Recursion

def digit_sum(n): n = abs(n) if n == 0: return 0 return n % 10 + digit_sum(n // 10) print(digit_sum(1234))

✅ Great for recursion practice.

🎯 Output
Sum of digits: 10


🔑 Key Takeaways
Use % 10 to get the last digit.

Use // 10 to remove the last digit.

sum(int(i) for i in str(n)) is easiest.

Use abs(n) for negative numbers.

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