Check if Number is Prime in DSA Python - Build from Scratch

Check if Number is Prime

📖 Scenario: You are helping a friend who wants to check if a number is prime. A prime number is a number greater than 1 that has no divisors other than 1 and itself.Imagine you have a list of numbers and want to find out which ones are prime.

🎯 Goal: Build a simple program that checks if a given number is prime by testing divisibility from 2 up to the number minus one.

📋 What You'll Learn

Create a variable called number with the exact value 29.

Create a variable called is_prime and set it to True.

Use a for loop with variable i to check divisors from 2 to number - 1.

Inside the loop, if number is divisible by i, set is_prime to False and break the loop.

Print "Prime" if is_prime is True, otherwise print "Not Prime".

💡 Why This Matters

🌍 Real World

Prime numbers are important in cryptography, computer security, and coding theory.

💼 Career

Understanding prime checking helps in algorithm design and problem solving in software development.

1

Create the number variable

Create a variable called number and set it to the exact value 29.

DSA Python

# Create a variable called number and set it to 29
# Your code here

Hint

Use number = 29 to create the variable.

2

Set up the prime flag

Create a variable called is_prime and set it to True.

DSA Python

number = 29
# Create a variable called is_prime and set it to True
# Your code here

Hint

Use is_prime = True to start assuming the number is prime.

3

Check divisors with a loop

Use a for loop with variable i to check divisors from 2 to number - 1. Inside the loop, if number % i == 0, set is_prime to False and break the loop.

DSA Python

number = 29
is_prime = True
# Use a for loop with i from 2 to number - 1
# Inside the loop, check if number is divisible by i
# If yes, set is_prime to False and break
# Your code here

Hint

Use for i in range(2, number): and check divisibility with number % i == 0.

4

Print if the number is prime

Print "Prime" if is_prime is True, otherwise print "Not Prime".

DSA Python

number = 29
is_prime = True
for i in range(2, number):
    if number % i == 0:
        is_prime = False
        break
# Print "Prime" if is_prime is True else print "Not Prime"
# Your code here

Hint

Use an if statement to print "Prime" or "Not Prime" based on is_prime.