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Different Methods to Find Prime Numbers in Python

First, we need to know what a prime number is.

A prime number is always a positive integer and can be divided by2An integer (1Divisible by the number itself)1Is not a prime number.

Now let's discuss some methods to find prime numbers.

Method1

Using For loop

Example

def primemethod1(number):
   # Initialize a list
   my_primes = []
   for pr in range(2, number):
      isPrime = True
   for i in range(2, pr):
   if pr % i == 0:
      isPrime = False
   if isPrime:
      my_primes.append(pr)
   print(my_primes)
primemethod1(50)

Output result

[2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47]

Method2

For loop with break

Example

def primemethod2(number):
   # Initialize a list
   my_primes = []
   for pr in range(2, number + 1)
      isPrime = True
   for num in range(2, pr):
   if pr % num == 0:
      isPrime = False
   break
      if isPrime:
   my_primes.append(pr)
return(my_primes)
print(primemethod2(5, 0))

Output result

[2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47]

Method3

For loop, break, and square root

Example

def primemethod3(number):
   # Initialize a list
   primes = []
   for pr in range(2, number):
      isPrime = True
   for num in range(2, int(pr ** 0.5) + 1)
   if pr % num == 0:
      isPrime = False
      break
   if (isPrime):
print("Prime number: ", pr)
primemethod3(50)

Output result

Prime number: 2
Prime number: 3
Prime number: 5
Prime number: 7
Prime number: 11
Prime number: 13
Prime number: 17
Prime number: 19
Prime number: 23
Prime number: 29
Prime number: 31
Prime number: 37
Prime number: 41
Prime number: 43
Prime number: 47