#! /usr/bin/env python
# -*- coding: utf-8 -*-
import datetime

def sample_loop(n):
L = []
for i in range(n):
L.append(i)
return L
def sample_comprehension(n):
L = []
return [L.append(i) for i in range(n)]

d = datetime.datetime.today()
print (":",d.strftime("%Y-%m-%d %H:%M:%S") )

sample_comprehension(50000000)
d = datetime.datetime.today()
print (":",d.strftime("%Y-%m-%d %H:%M:%S") )

sample_loop(50000000)
d = datetime.datetime.today()
print (":",d.strftime("%Y-%m-%d %H:%M:%S") )

結果
2010-06-27 21:01:04
2010-06-27 21:02:11
2010-06-27 21:02:12