Dear python tutors,
for training purposes, I am writing a Python program for prime factorisation.
Functions for reading in the number and finding the primes are working alright
(of Course, finding primes up to ½ Number would suffice).
Still, the function for finding the factorization itsel does not work. I am not
sure, but the number i running through the primes for checking does not seem to
work properly.
Would you please be so kind as to help?
Thank you very much.
Best wishes,
Bernd
# This program calculates the prime factors of a number entered.
primefactors = []
n, num = 0, 0
def readin():
print ("Readin")
while True:
num = input("Please enter a positive integer n for prime factorization.
")
try:
n = int(num)
return n
except ValueError or num < 1:
print("Please enter a _positive_ integer!")
else:
break
def prime_find(l):
#print ("Primefind " + str(l))
primes = []
for num in range(2, l + 1):
for i in primes:
if (num % i) == 0:
break
else:
primes.insert(0, num)
return primes
def prime_factorization(k):
print ("Prime factorization")
prime_facs = []
for i in range(len(prime_find(k)):
while k % i == 0:
prime_facs.insert(0, i)
k = k / i
else:
break
return prime_facs
number = readin()
primes = prime_find(number)
print ("Prime numbers up to " + str(number) + " are:")
print (primes)
prime_factor = prime_factorization(number)
print (prime_factor)
"""def PrimFaktorZerlegung(n):
#Primen enthält Primzahlen. Wir hoffen, dass
#alle Primteiler in diese List zu finden sind.
#Sie kann ein Parameter, oder ein Klasskonstant sein
for p in range(len(Primen)):
while n % p == 0:
Teiler.append(p)
n = n/p
return Teiler"""
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