View difference between Paste ID: kWUsHsL4 and zQuHQ46H

 import re
 
 #gen_primes is modified from http://stackoverflow.com/a/568618/203705
 def gen_primes(start, end):
 
     # Maps composites to primes witnessing their compositeness.
     # This is memory efficient, as the sieve is not "run forward"
     # indefinitely, but only as long as required by the current
     # number being tested.
     #
     D = {}
 
     # The running integer that's checked for primeness
     q = 2
     primes = []
 
     while q != end:
         if q not in D:
             # q is a new prime.
             # Yield it and mark its first multiple that isn't
             # already marked in previous iterations
             #
             if q >= start:
                 primes.append(q)
             D[q * q] = [q]
         else:
             # q is composite. D[q] is the list of primes that
             # divide it. Since we've reached q, we no longer
             # need it in the map, but we'll mark the next
             # multiples of its witnesses to prepare for larger
             # numbers
             #
             for p in D[q]:
                 D.setdefault(p + q, []).append(p)
             del D[q]
 
         q += 1
     return primes
 
 def get_danish_nums(name):
     nums = {}
     with open(name, 'r') as f:
         lines = f.readlines()
 
     for line in lines:
         vals = line.split(',')
         if vals[2].strip() != 'Reserve / Reserve':
             if len(vals[0].strip()) == 8:
                 start = int(re.sub(r'[a-z]','0',vals[0]))
                 end = int(re.sub(r'[a-z]','9',vals[0]))
                 if start == end:
                     nums[start] = True
                 else:
                     for num in range(start, end+1):
                         nums[num] = True
     return nums
 
 
 if __name__ == '__main__':
     print("Getting nums...")
     #CSV built from spreadsheet found here:
     #http://www.erhvervsstyrelsen.dk/numbering_lists
     nums = get_danish_nums('danish_numberlist.csv')
     start = min(nums)
     end = max(nums)
 
     print("Getting primes...")
     primes = gen_primes(start,end)
     i = 0
     print("Checking...")
     for prime in primes:
         if nums.get(prime, False):
             print("%s is valid prime phone number!" % prime)
             i+=1
     print("%s of %s valid danish phone numbers are prime." % (i, len(nums)))