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POPrime numbers calculation with python
 

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    <p>I know, there are a lot of questions about prime numbers already, but I don't ask for a code. I just want to know, what is wrong with the mine (I hope comments would help you understand, what I'm doing):</p> <pre><code>from math import ceil def isPrimeNumber (n, out='short'): #Checks, whether n is a prime number answer = 'Yes' for p in range(2, int(ceil(n**0.5))+1): #Checks all numbers lower than #SQRT(n), if they are divisors of n if n%p == 0: #If p is a divisor, n isn't prime answer = 'No' if out == 'verbose': print 'Least divisor is', p return False break if answer == 'Yes': #If there isn't a p, that is a divisor, n is prime if out == 'verbose': print 'No divisors except for 1 and', str(n)+'!' return True def primeNumbers (start = 1, stop = 1000, numbers = 0): N = stop if numbers == 0: #Calculates all prime numbers in N numbers in a row #(N=1000 -&gt; calculates all prime numbers in 1000 numbers, #by default from 1 to 997) primes = [] for i in range(start, N+1): if isPrimeNumber(i) == True: primes.append(i) elif numbers == 1: #Calculates N prime numbers in a row #(N=1000 -&gt; calculates 1000 prime numbers) primes = [start] i = len(primes) j = 1 while i &lt;= N: #Stops, when we get N prime numbers - doesn't work! n = max(primes) + 1 while j != 'stop': if isPrimeNumber(n, out='short') == True: primes.append(n) i = i + 1 j = 'stop' #Stops nested cycle, when reached #the first prime number else: n = n + 1 else: print 'Wrong input! 3rd number in function call must be either 0 or 1' return primes </code></pre> <p>Function isPrimeNumber() works fine. Function primeNumbers works fine as well, when numbers=0. But if numbers=1, then, as it seems, one of the cycles never stops, I can't understan why...</p>
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    1. COAs a start, you should follow PEP 8 to write more readable code.
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    2. COAlso, don't use strings like `'Yes'` or `'No'`, but prefer booleans (`True` and `False`).
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    3. COI'm trying to follow it, but I've just started programming and first I'd like to learn to write the working code. But thank you! Um, don't know, why I didn't use booleans there, as I use them in a different place in the same program... Thanks!
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