Python code for prime number

Python Program to Check Prime Number We will write a program here in which we will check that a given number is a prime number or not. Prime numbers: If the natural number is greater than 1 and having no positive divisors other than 1 and the number itself etc. For example: 3, 7, 11 etc are prime numbers. Composite number: Other natural numbers that are not prime numbers are called composite numbers. For example: 4, 6, 9 etc. are composite numbers. Let us look at the following example to understand the implementation. Example: # A default function for Prime checking conditions def PrimeChecker(a): # Checking that given number is more than 1 if a > 1: # Iterating over the given number with for loop for j in range(2, int(a/2) + 1): # If the given number is divisible or not if (a % j) == 0: print(a, "is not a prime number") break # Else it is a prime number else: print(a, "is a prime number") # If the given number is 1 else: print(a, "is not a prime number") # Taking an input number from the user a = int(input("Enter an input number:")) # Printing result PrimeChecker(a) Output: Enter an input number:17 17 is a prime number Explanation: We have used nested if else condition to check if the number is a prime number or not. First, we have checked if the given number is greater than 1 or not. If it is not greater than 1, then the number will directly come to the else part and print 'not a prime number.' Now, the number will enter into for loop where we perform Iteration from 2 to...

def checkPrime(num): # 0, 1 and negative numbers are not prime if num < 2: return 0 else: # no need to run loop till num-1 as for any number x the numbers in # the range(num/2 + 1, num) won't be divisible anyway # Example 36 won't be divisible by anything b/w 19-35 x = num // 2 for j in range(2, x + 1): if num % j == 0: return 0 # the number would be prime if we reach here return 1 a, b = 1, 100 for i in range(a, b + 1): if checkPrime(i): print(i, end=" ") Output 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 def checkPrime(num): # 0, 1 and negative numbers are not prime if num < 2: return 0 else: # no need to run loop till num-1 as for any number x the numbers in # the range(num/2 + 1, num) won't be divisible anyway # Example 36 won't be divisible by anything b/w 19-35 x = num // 2 for j in range(2, x + 1): if num % j == 0: return 0 # the number would be prime if we reach here return 1 for i in range(1, 100 + 1): if checkPrime(i): print(i, end=" ") Output 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97 Method used to check prime A number n is not a prime if it can be factored into two factors a & b: n = a * b Now a and b can't be both greater than the square root of n, since then the product a * b would be greater than sqrt(n) * sqrt(n) = n. So in any factorization of n, at least one of the factors must be smaller than the square root of n, and if we can't find any factors less than or equal to the square root, n must be a pr...

In this tutorial, you’ll learn how to use Python to find prime numbers, either by checking if a single value is a prime number or finding all prime numbers in a range of values. Prime numbers are numbers that have no factors other than 1 and the number itself. Being able to work with prime numbers is a common task in occupations such as computer and cyber security. By the end of this tutorial, you’ll have learned: • What prime numbers are • Different ways of finding prime numbers in Python • Optimizing our algorithms for finding prime numbers in Python • Finding all prime numbers between a range of values in Python Table of Contents • • • • • • What are Prime Numbers Prime numbers are a positive integer that’s greater than 1 that also have no other factors except for 1 and the number itself. For example, the number 5 is a prime number, while the number 6 isn’t (since 2 x 3 is equal to 6). The first few prime numbers are: 3, 7, 11, 13, etc. Finding Prime Numbers in Python (Optimized Code) Let’s take a look at how we can use Python to determine if a number is a prime number. The most naive and straightforward implementation is to loop over the range of numbers from 2 to the number and see if the modulo of the number and the range is equal to 0. If that occurs, then the number has a divisor other than 1 and the number itself and the number isn’t a prime number. Let’s take a look at how we can implement this first code: # Writing a Simple Function to Check if a Number is a Pri...

In this post, we will write a program in Python to check whether the input number is prime or not. A number is said to be prime if it is only divisible by 1 and itself. For example 13 is a prime number because it is only divisible by 1 and 13, on the other hand 12 is not a prime number because it is divisible by 2, 4, 6 and number itself. Checking if number is prime or not A prime number is always positive so we are checking that in the beginning of the program. We are dividing the input number by all the numbers in the range of 2 to (number – 1) to see whether there are any positive divisors other than 1 and number itself. If any divisor is found then we display that the “number is not a prime number” else we display that the “number is a prime number”. We are using the break statement in the loop to come out of the loop as soon as any positive divisor is found as there is no further check is required. # taking input from user number = int(input("Enter any number: ")) # prime number is always greater than 1 if number > 1: for i in range(2, number): if (number % i) == 0: print(number, "is not a prime number") break else: print(number, "is a prime number") # if the entered number is less than or equal to 1 # then it is not prime number else: print(number, "is not a prime number") Output: Related Posts: • • • • •

Closed 8 years ago. I'm trying to write a generator function for printing prime numbers as follows def getPrimes(n): prime=True i=2 while(i

Write a function in JavaScript • ActionScript • Ada • AppleScript • Arduino • Assembly x86 • AutoHotkey • Bash • Basic • Brainfuck • C • C# • C++ • Clojure • COBOL • CoffeeScript • Dart • Elixir • Erlang • Go • Haskell • Java • JavaScript • Julia • Kotlin • LaTeX • Lua • MoonScript • Objective C • Perl • PHP • PineScript • PowerShell • Prolog • Python • R • Ruby • Rust • Scala • Scratch • SQL • Swift • TypeScript • VBScript • ZenScript This function takes two integers as arguments and returns all prime numbers between them. The function first checks if both arguments are integers and if m is less than or equal to n. It then initializes an empty list to store prime numbers and loops through the range from m to n. For each number in the range, it checks if the number is greater than 1 and if it is prime. If the number is prime, it is added to the list of prime numbers. Finally, the list of prime numbers is returned as a string separated by a space. Use this function to quickly and easily find all prime numbers between two given integers in Python. Original answer def get_primes(m, n): """ This function takes two integers as arguments and returns all prime numbers between them. Parameters: m (int): The lower limit of the range n (int): The upper limit of the range Returns: str: A string of prime numbers separated by a space """ try: # Check if both arguments are integers if not isinstance(m, int) or not isinstance(n, int): raise TypeError("Both arguments must be integers") # ...

I'm a beginning programmer in python and have a question about my code I'm writing: number = int(input("Enter a random number: ")) for num in range(1, number + 1) : for i in range(2, num) : if (num % i) == 0 : break else : print(num) break When I run this program I also get 9, 15 21 as output. But these are not prime numbers. What is wrong with my code? Thanks! With if (num % i) == 0: you go to the else block for every num, which is not a multiply of 2, as you start i with 2, thus printing num. I got all odd numbers printed with your code. You can use something like this: number = int(input("Enter a random number: ")) for num in range(1, number + 1): prime = True for i in range(2, num): if (num % i) == 0: prime = False break if prime: print(num) It sets prime to False when it encounters a divisor without rest. Your problem The else statement that you put inside the for loop means that if that number(num) is divisible by this current no represented by i, return true considering it as a prime which IS NOT CORRECT. Suggestion Your outer loop starts with 1 which should change to 2, as 1 is not a prime number Solution def fun(number): #Not counting 1 in the sequence as its not prime for num in range(2, number + 1) : isPrime = True for i in range(2, num) : if (num % i) == 0 : isPrime = False break if isPrime: print num fun(10) Output 1 2 3 5 7 I am assuming the random number is the range you want the numbers to be within. I found that the variable i is always equal to 2 in your ...