python列表推導 和 內置函數map,filter 效率對比（轉）

前言 在python中的列表操做主要有兩種， 一種相似於lisp的函數編程方法：filter( function,list) , map( function, list) 另外一種特別pythonic——列表推導 [ i for i in list ] 如今就兩種方法進行對比，看看哪一種效率高 filter 和 列表推導 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] # 列表推導 8 print time.time() - start 9 #print list1 10 結果： ; map 和列表推導 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

結論 其實二者差異不太大，能夠歸結爲編碼風格問題，可是我我的比較喜歡pythonic的列表推導，恰好它的效率也高點！