转载自:http://blog.csdn.net/wzgbm/article/details/54691615
首先给一个简单的例子,测测list和dict查找的时间:
import time query_lst = [-60000,-6000,-600,-60,-6,0,6,60,600,6000,60000] lst = [] dic = {} for i in range(100000000): lst.append(i) dic[i] = 1 start = time.time() for v in query_lst: if v in lst: continue end1 = time.time() for v in query_lst: if v in dic: continue end2 = time.time() print "list search time : %f"%(end1-start) print "dict search time : %f"%(end2-end1)
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
- 22
- 23
- 24
- 25
- 26
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
- 22
- 23
- 24
- 25
- 26
运行结果:
list search time : 11.836798
dict search time : 0.000007
通过上例我们可以看到list的查找效率远远低于dict的效率,原因如下:
Python中list对象的存储结构采用的是线性表,因此其查询复杂度为O(n),而dict对象的存储结构采用的是散列表(hash表),其在最优情况下查询复杂度为O(1)。
时间: 2024-11-08 22:38:36