當找到一個數的主要因素時，一些數字會起作用，而另一些則不起作用

Question

測試數字時，有些可以工作，例如48，而有些則不能。 我不確定找到數字的所有因素的最佳方法是什么。

素因數分解

def find_primes(n): 
    factors = []
    i = 2
    if n == 0:
        return 0              
    if n == 1:
        return 1                
    if n >= 2:
        while n % i == 0:
            next_n = n / i
            factors.append(i)
            n = next_n 
            if n % i != 0:
                i += 1
                continue
            elif i == n:
                break
    if len(factors) == 0:
        return "{} is a prime number.\n".format(initial_n)
    else:
        return "The prime factors of {} are: {}\n".format(initial_n, factors)


n = int(input("Enter a number to find all the Prime Factors:"))
initial_n = n
print('\n')
print(find_primes(n))

我期望得到一個數字的所有因素的清單。

Answer 1

我更改了您的代碼，現在它適用於所有自然數：

def find_primes(n): 
    factors = []
    i = 2
    if n == 0:
        return 0
    if n == 1:
        return 1
    if n >= 2:
        while i * i <= n:
            while n % i == 0:
                factors.append(i)
                n = n // i
            i += 1
    if n > 1:
        factors.append(n)
    if len(factors) == 1:
        return "{} is a prime number.\n".format(initial_n)
    else:
        return "The prime factors of {} are: {}\n".format(initial_n, factors)


n = int(input("Enter a number to find all the Prime Factors:"))
initial_n = n
print('\n')
print(find_primes(n))

Answer 2

def find_primes(n):
    factors = []
    i = 2
    if n == 0:
        return 0
    if n == 1:
        return 1
    while i <= n:
        if n % i == 0:
            factors.append(i)
            n /= i
        else:
            i += 1
    if len(factors) == 0:
        return "{} is a prime number.\n".format(initial_n)
    else:
        return "The prime factors of {} are: {}\n".format(initial_n, factors)


n = int(input("Enter a number to find all the Prime Factors:"))
initial_n = n
print('\n')
print(find_primes(n))

Answer 3

下面的主要因子計算功能比上面的簡單得多。 剩下的只是對用戶輸入的完整性檢查。

###########################################################
#Main function to calculate prime factors
def find_prime_factors(n):
    factors = []
    p = 2
    while n > p ** 2:
        if n % p == 0:
            factors.append(p)
            n //= p
        else:
            p += 1
    factors.append(n)
    return factors
###########################################################

# Get User input
n = input('Enter a number to find all the Prime Factors: ') 

# Check if the entered value is a number
while not n.isnumeric():
    print('Entered number was not numeric.')
    n = input('Enter a NUMBER to find all the Prime Factors: ') 

# Check the entered value is greater than one (1)
# Prime Factor check happens on only positive numbers that are greater than one (1)

while int(n) < 2:
    print("Please enter a positive number that is greater than one (1).")
    n = input('Enter a NUMBER to find all the Prime Factors: ') 

#Python 3.7 string formating
print(f'The prime factor(s) of {n}: {find_prime_factors(int(n))} ')