import functools
import random
import sys
import timeit

if sys.version_info < (3, 0):
    range = xrange

def revind(L, n):
    indices = [index for index, item in enumerate(L) if item==n]
    for index in reversed(indices):
        del L[index]

def whiledel(L, n):
    i = 0
    while i < len(L):
        if L[i] == n:
            del L[i] # Do not increment i here, because L[i] will change
        else:
            i += 1
        
def slide(L, n):
    # indices takes *worse-case* O(N) space, but typical-case much less
    indices = [i for i, x in enumerate(L) if x==n]
    indices_seen = 0
    num_indices = len(indices)
    for i in range(len(L)):
        if (indices_seen < num_indices and 
            i + indices_seen == indices[indices_seen]):
            indices_seen += 1
        if i+indices_seen >= len(L):
            break
        L[i] = L[i+indices_seen]            
    L[-indices_seen:] = []

def genexpr(L, n):
    L[:] = (i for i in L if i != n)

def listcomp(L, n):
    L[:] = [i for i in L if i != n]

if sys.version_info < (3, 0):
    def filterer(L, n):
        L[:] = filter(lambda i: i != n, L)
else:
    def filterer(L, n):
        L[:] = filter(n.__ne__, L)

def remove(L, n):
    while True:
        try:
            L.remove(n)
        except ValueError:
            break

def removein(L, n):
    while n in L:
        L.remove(n)

maxnum = int(sys.argv[1]) if len(sys.argv) > 1 else 16
listlen = int(sys.argv[2]) if len(sys.argv) > 2 else 1000000
reps = int(sys.argv[3]) if len(sys.argv) > 3 else 3

L0 = [random.randrange(maxnum) for _ in range(listlen)]
for f in revind, whiledel, slide, genexpr, listcomp, filterer, remove, removein:
    L = L0[:]
    p = functools.partial(f, L, 0)
    print('{}: {} ({})'.format(f.__name__, timeit.timeit(p, number=reps), len(L)))