python链表法的优缺点
1、优点,方便删除记录,直接处理数组对应下标的子数组。平均搜索速度快。如果有冲突,只需要查询子数组。
2、缺点,使用指针导致查询速度较慢,内存占用可能较高,不适合序列化。
而开放式寻址法的优缺点与链表法相反。因为Python的一切都是基于Dict的,都需要序列化,所以选择了开放式寻址法。
实例
代码语言:javascript复制 # keys函数
#!/usr/bin/env python
# coding=utf-8
class Dict:
def __init__(self, num):
self.__solts__ = []
self.num = num
for _ in range(num):
self.__solts__.append([])
def hash_fun(self,key,num):
hashval = 0
x = key
if x < 0:
print "the key is low"
return
while x != 0:
hashval = (hashval << 3) x
x /=10
return hashval % num
def put(self, key, value):
i = self.hash_fun(key,self.num) % self.num
for p, (k, v) in enumerate(self.__solts__[i]):
if k == key:
break
else:
self.__solts__[i].append((key, value))
return
self.__solts__[i][p] = (key, value)
def get(self, key):
i = self.hash_fun(key,self.num) % self.num
for k, v in self.__solts__[i]:
if k == key:
return v
raise KeyError(key)
# keys函数
def keys(self):
ret = []
for solt in self.__solts__:
for k, _ in solt:
ret.append(k)
return ret
def __getitem__(self,key):
return self.get(key)
def __setitem__(self,key,data):
self.put(key,data)
H = Dict(13)
H[54] = "cat"
H[26] = "dog"
H[93] = "lion"
H[17] = "tiger"
H[77] = "bird"
H[31] = "cow"
H[44] = "goat"
H[55] = "pig"
H[20] = "chicken"
print H.get(54)
H.put(13,"duck")
print H.__solts__
print H.keys()
以上就是python链表法的优缺点,希望对大家有所帮助。更多Python学习指路:python基础教程
本文教程操作环境:windows7系统、Python 3.9.1,DELL G3电脑。