import time

time.clock()

for numelements in (1000,10000,100000,1000000):
    print numelements
    L = range(numelements)

    start = time.clock()

    I = set()
    for i in range(len(L)):
        # if not L[i].isValid():
        if i % 11 == 0:
            I.add(i)
            
    for i in sorted(I, reverse=True):
        del L[i]

    end = time.clock()
    print end-start

    L = range(numelements)

    start = time.clock()

    L = [ item for i,item in enumerate(L) if i % 11 != 0 ]

    end = time.clock()
    print end-start
    print