Question

solutions to problem set 1.... please just post solution... been trying for a few days now

Answer 1

both problems

Answer 2

Here is what i finally managed to get a hold of for part 1:


def primes(n):
"""
returns a list of prime numbers from 2 to n
"""
if n < 2: return []
if n == 2: return [2]
# create a list of odd numbers from 3 to n
nums = list(range(3, n+1, 2))
nums_len = (n // 2) - 1 + (n % 2)
idx = 0
idx_sqrtn = (int(n**0.5) - 3) // 2
while idx <= idx_sqrtn:
nums_idx = (idx << 1) + 3
for j in range(idx*(nums_idx+3)+3, nums_len, nums_idx):
# if not a prime replace with zero
nums[j] = 0
idx += 1
while idx <= idx_sqrtn:
if nums[idx] != 0:
break
idx += 1
# remove all the zero entries
return [2] + [x for x in nums if x != 0]


print('-' * 50) # print 50 dashes, cosmetic
num = 7919
primeList = primes(num)
print("List of prime numbers from 2 to %d:" % num)
print(primeList)