Find nth prime number in python
Hi, today we will learn about how to find an nth prime number in python. Finding a prime number is very easy in python. A prime number is a number which can only be divided by 1 and the number itself.
Python program to find nth prime number
n = int(input('Enter : ')) prime_numbers = [2,3] i=3 if(0<n<3): print(n,'th Prime Number is :',prime_numbers[n-1]) elif(n>2): while (True): i+=1 status = True for j in range(2,int(i/2)+1): if(i%j==0): status = False break if(status==True): prime_numbers.append(i) if(len(prime_numbers)==n): break print(n,'th Prime Number is :', prime_numbers[n-1]) else: print('Please Enter A Valid Number')
Enter : 10 10 th Prime Number is : 29
- At first, we take the input into the ‘n’ variable.
- We create a python list variable ‘prime_numbers’.
- Initially, we store 2,3 into the ‘prime_numbers’ variable.
- We create an ‘i’ variable. Initially, we store 3 into the ‘i’ variable.
- We create an if condition. If the value of n is greater than 0 and less than 3, it means if the value of n in between 1 to 2 then the operation will be performed. If the condition satisfied then print the list prime_numbers’s n-1 th position value.
- We create an elif condition. If the value is greater than 2 then the task is performed.
- We create an infinite While Loop. For storing the prime number into the ‘prime_numbers’ variable.
- increase the value of ‘i’ by one.
- We create a boolean variable ‘status’. Initially, it is ‘True’.
- We create a For Loop. The starting value of for loop variable ‘j’ is 2 and ending with (half+1) of the ‘i’ value. This for loop is used for checking the ‘i’ number is prime or not prime.
- If the remainder of (‘i’ value / ‘j’ value) is Zero then it not be a prime number. And break the for loop and ‘status‘ will be ‘False’.
- For all value of ‘j’, if the remainder not going to zero then the ‘status‘ will be ‘True’.
- We check if the status True then it is a prime number. And it stored into the ‘prime_numbers’.
- We check if the length of the list is equal to the ‘n’ value then the while loop will break.
- After breaking the while loop we print the nth prime number.
- We create an else section if the user types any wrong or negative value then program will print ‘Please Enter A Valid Number’.
In this whole process, we can easily find the nth prime number.
You may like to read :
- Catalan Number in Python – Iterative Approach (Factorial)
- Check whether two strings are anagram of each other using Python 3.x or earlier