问题：Python中的哈希图
我想在Python中实现HashMap。我想请用户输入。根据他的输入，我正在从HashMap中检索一些信息。如果用户输入HashMap的键，我想检索相应的值。
如何在Python中实现此功能？
HashMap<String,String> streetno=new HashMap<String,String>();
streetno.put("1", "Sachin Tendulkar");
streetno.put("2", "Dravid");
streetno.put("3","Sehwag");
streetno.put("4","Laxman");
streetno.put("5","Kohli")回答 0
Python字典是一种内置类型，支持键值对。
streetno = {"1": "Sachin Tendulkar", "2": "Dravid", "3": "Sehwag", "4": "Laxman", "5": "Kohli"}以及使用dict关键字：
streetno = dict({"1": "Sachin Tendulkar", "2": "Dravid"}) 要么：
streetno = {}
streetno["1"] = "Sachin Tendulkar" 回答 1
您想要的（在最初提出问题时）只是一个提示。提示：在Python中，您可以使用字典。
回答 2
它是Python内置的。参见字典。
根据您的示例：
streetno = {"1": "Sachine Tendulkar",
"2": "Dravid",
"3": "Sehwag",
"4": "Laxman",
"5": "Kohli" }然后，您可以像这样访问它：
sachine = streetno["1"]还值得一提：它可以使用任何非可变数据类型作为键。也就是说，它可以使用元组，布尔值或字符串作为键。
回答 3
streetno = { 1 : "Sachin Tendulkar",
2 : "Dravid",
3 : "Sehwag",
4 : "Laxman",
5 : "Kohli" }并获取值：
name = streetno.get(3, "default value")要么
name = streetno[3]那就是使用数字作为键，在数字两边加上引号以使用字符串作为键。
回答 4
哈希图是Python内置的，它们称为字典：
streetno = {} #create a dictionary called streetno
streetno["1"] = "Sachin Tendulkar" #assign value to key "1"用法：
"1" in streetno #check if key "1" is in streetno
streetno["1"] #get the value from key "1"请参阅文档以获取更多信息，例如内置方法等。它们很棒，并且在Python程序中非常常见（毫不奇怪）。
回答 5
这是使用python实现的Hash Map的实现。为简单起见，Hash Map的大小固定为16。可以轻松更改。重新哈希不在此代码范围内。
class Node:
def __init__(self, key, value):
self.key = key
self.value = value
self.next = None
class HashMap:
def __init__(self):
self.store = [None for _ in range(16)]
def get(self, key):
index = hash(key) & 15
if self.store[index] is None:
return None
n = self.store[index]
while True:
if n.key == key:
return n.value
else:
if n.next:
n = n.next
else:
return None
def put(self, key, value):
nd = Node(key, value)
index = hash(key) & 15
n = self.store[index]
if n is None:
self.store[index] = nd
else:
if n.key == key:
n.value = value
else:
while n.next:
if n.key == key:
n.value = value
return
else:
n = n.next
n.next = nd
hm = HashMap()
hm.put("1", "sachin")
hm.put("2", "sehwag")
hm.put("3", "ganguly")
hm.put("4", "srinath")
hm.put("5", "kumble")
hm.put("6", "dhoni")
hm.put("7", "kohli")
hm.put("8", "pandya")
hm.put("9", "rohit")
hm.put("10", "dhawan")
hm.put("11", "shastri")
hm.put("12", "manjarekar")
hm.put("13", "gupta")
hm.put("14", "agarkar")
hm.put("15", "nehra")
hm.put("16", "gawaskar")
hm.put("17", "vengsarkar")
print(hm.get("1"))
print(hm.get("2"))
print(hm.get("3"))
print(hm.get("4"))
print(hm.get("5"))
print(hm.get("6"))
print(hm.get("7"))
print(hm.get("8"))
print(hm.get("9"))
print(hm.get("10"))
print(hm.get("11"))
print(hm.get("12"))
print(hm.get("13"))
print(hm.get("14"))
print(hm.get("15"))
print(hm.get("16"))
print(hm.get("17"))输出：
sachin
sehwag
ganguly
srinath
kumble
dhoni
kohli
pandya
rohit
dhawan
shastri
manjarekar
gupta
agarkar
nehra
gawaskar
vengsarkar回答 6
class HashMap:
def __init__(self):
self.size = 64
self.map = [None] * self.size
def _get_hash(self, key):
hash = 0
for char in str(key):
hash += ord(char)
return hash % self.size
def add(self, key, value):
key_hash = self._get_hash(key)
key_value = [key, value]
if self.map[key_hash] is None:
self.map[key_hash] = list([key_value])
return True
else:
for pair in self.map[key_hash]:
if pair[0] == key:
pair[1] = value
return True
else:
self.map[key_hash].append(list([key_value]))
return True
def get(self, key):
key_hash = self._get_hash(key)
if self.map[key_hash] is not None:
for pair in self.map[key_hash]:
if pair[0] == key:
return pair[1]
return None
def delete(self, key):
key_hash = self._get_hash(key)
if self.map[key_hash] is None :
return False
for i in range(0, len(self.map[key_hash])):
if self.map[key_hash][i][0] == key:
self.map[key_hash].pop(i)
return True
def print(self):
print('---Phonebook---')
for item in self.map:
if item is not None:
print(str(item))
h = HashMap()回答 7
在这种情况下，Python Counter也是一个不错的选择：
from collections import Counter
counter = Counter(["Sachin Tendulkar", "Sachin Tendulkar", "other things"])
print(counter)这将返回一个字典，其中包含列表中每个元素的计数：
Counter({'Sachin Tendulkar': 2, 'other things': 1})回答 8
在python中，您将使用字典。
这是python中非常重要的类型，经常使用。
您可以轻松创建一个
name = {}字典有很多方法：
# add entries:
>>> name['first'] = 'John'
>>> name['second'] = 'Doe'
>>> name
{'first': 'John', 'second': 'Doe'}
# you can store all objects and datatypes as value in a dictionary
# as key you can use all objects and datatypes that are hashable
>>> name['list'] = ['list', 'inside', 'dict']
>>> name[1] = 1
>>> name
{'first': 'John', 'second': 'Doe', 1: 1, 'list': ['list', 'inside', 'dict']}您不能影响命令的顺序。
