🚀 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.