Question

Does anyone have an idea of computing prime numbers with python?

Answer 1

One possible implementation is the following:

def primes(n):
if n==2: return [2]
elif n<2: return []
s=range(3,n+1,2)
mroot = n ** 0.5
half=(n+1)/2-1
i=0
m=3
while m <= mroot:
if s[i]:
j=(m*m-3)/2
s[j]=0
while j<half:
s[j]=0
j+=m
i=i+1
m=2*i+3
return [2]+[x for x in s if x]

Taken from http://code.activestate.com/recipes/366178-a-fast-prime-number-list-generator/

Answer 2

Another nice web site.

http://www.thattommyhall.com/2010/10/18/prime-gen/

Please note that I haven't tested any of the above code myself!

Answer 3

just try out this

prime_count = 1
start_number = 2
number_to_check = 2
while prime_count <= 1000:
result = number_to_check % start_number

if result > 0:
start_number +=1

elif result == 0:
if start_number == number_to_check:
print (number_to_check)
number_to_check +=1
prime_count +=1
start_number =2
else:
number_to_check +=1
start_number = 2

Answer 4

http://dpaste.com/807530/

Answer 5

Check out this Khan academy CS lesson on computing prime numbers.
http://www.khanacademy.org/about/blog/post/32465397255/computer-science-prime-adventures-level-up

It is done in their javascript environment and not in python tho.

Answer 6

very cool! Thanks for all the help. :-)