The school professor taught us about prime numbers and composite numbers when I was a child. However, as I grew older and learned Python, I came across the queries of prime numbers programs in Python. Then I learned and practiced a variety of techniques.
Finally, I discovered two separate and superior methods for finding prime numbers in Python. I’m going to take you through those two ways one by one and step by step today. To provide greater clarity on the subject, I’ve listed the programs you may use and deploy to better understand the prime number in Python.
So, let’s start with today’s topic, but first, let’s define prime and composite numbers.
What are prime numbers?
The number itself is known as a Prime number if it is greater than one and has no other positive divisors than 1.
3, 7, 11, and so on are prime numbers.
What are the composite numbers?
Other natural numbers that are not prime numbers are called composite numbers.
Composite numbers, for example, are 4, 6, 9, and so on.
Some fascinating Prime Numbers Facts –
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Algorithm for checking whether a number is prime or not
Step 1: Get information or a value from the user.
Step 2: Make sure the number should be greater than one; if it isn’t, it isn’t a Prime number.
Step 3: Divide the number equally by any number between 2 and half of the amount.
Step 4: Take a print of the program outcome.
Check two different approaches for the prime number program in Python
- Using the flag variable:
Output:
Enter the input number: 54
54 is a composite number (or not a prime number)
You may use the above Python program to determine if a number is prime or not. Here, we have to proceed if the number is more than one.
Check if x is divisible by any number between 2 and x -1. Also, if the factor is found inside the range, the number is taken as the prime number. Set the flag to True and break the loop if the condition is true.
But don’t forget to look outside the loop for the flag value.
- If the flag is set to true, then x is not a prime number.
- If the flag is set to false, the x value will be a prime number.
Note: You may lower the number range to look at other parameters to check the program’s efficiency. We shall search the range from 2 to x -1. You may also use range (2, x/2) or range(2,math.floor(math.sqrt(x)+1) as an alternative.
The range is determined by the fact that composite numbers must have a component. And it must be equal to or less than the square root of the number in question. Alternatively, it might be the prime number.
In the above prime number program in Python, you may change the value of the variable x. And check to see if the integer is prime.
We can also use the for…else statement to get the prime number in Python. This is possible without the use of a Python flag variable.
- Using a for…else statement:
Output:
Enter an input number: 52
52 is a composite number (not a prime number)
2 times 26 is 52
The prime number program in Python can also be executable using a for…else statement. You can check it in the example above. It works with logic, with the else clause running the for loop while the break clause exits the for a loop.
If there is no factor, this condition will hold. And it will define that the number supplied will be prime. As a result, you may declare the number as prime using the for…else clause.
This is how you can easily get the prime number using the prime number program in Python.
Let’s conclude it up!
One of the essential jobs in every programming language is to find the prime number. That is why the prime number program in Python is always assigned to students and beginners with a better understanding of programming languages. If you are unable to do so, employ the methods listed above. This will assist you in checking prime and composite numbers.
Do you have any more questions about prime numbers in Python? Ask it with one of the specialists of CodeAvail to clear up any questions you may have. And, if you have any questions or issues about the above information, please let us know through email.
