Question 7

Convert the following English description into code.

1. Initialize n to
   be 1000. Initialize numbers to
   be a list of numbers from 2 to n, but not including n.
2. With results starting
   as the empty list, repeat the following as long as numbers contains
   any numbers.
   • Add the first number in numbers to
     the end of results.
   • Remove every number in numbers that
     is evenly divisible by (has no remainder when divided by) the number that you had just added to results.

How long is results?

To test your code, when n is
instead 100, the length of results is
25.

代码：

lis = list(range(2,1000))

print lis[0]

res =[]

print len(res)

res.append(lis[0])

while len(lis)>1:

    for i in lis:

        if i % res[-1]==0:

            lis.remove(i)

    res.append(lis[0])

print lis

print len(res)