python列表推导 和 内置函数map,filter 效率对比（转）

前言 在python中的列表操做主要有两种， 一种相似于lisp的函数编程方法：filter( function,list) , map( function, list) 另外一种特别pythonic——列表推导 [ i for i in list ] 如今就两种方法进行对比，看看哪一种效率高 filter 和 列表推导 file: filter-1.py 1 #coding=utf-8 2 import time 3 4 list = [i for i in range(1,50000)] 5 start = time.time() 6 for i in range(0,1000): 7 list1 = filter(lambda i: i%2==0, list) # filter 8 print time.time() - start 9 #print list1 10 file: filter-2.py 1 #coding=utf-8 2 import time 3 4 list = [i for i in range(1,50000)] 5 start = time.time() 6 for i in range(0,1000): 7 list1 = [i for i in list if i % 2 == 0] # 列表推导 8 print time.time() - start 9 #print list1 10 结果： ; map 和列表推导 1 #File: map-1.py 2 #coding=utf-8 3 import time 4 5 list = [i for i in range(1,500000)] 6 start = time.time() 7 for i in range(0,1000): 8 list1 = map(lambda i: i*2, list) 9 print time.time() - start 10 #print list1 11 #File: map-2.py #coding=utf-8 import time list = [i for i in range(1,50000)] start = time.time() for i in range(0,1000): list1 = [ i*2 for i in list ] print time.time() - start #print list1

结论 其实二者差异不太大，能够归结为编码风格问题，可是我我的比较喜欢pythonic的列表推导，恰好它的效率也高点！