English | 简体中文 | 繁體中文 | Русский язык | Français | Español | Português | Deutsch | 日本語 | 한국어 | Italiano | بالعربية
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.
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]
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]
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