我想在Python中实现一个HashMap。我想让用户输入。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的一个键，我想检索相应的值。
我如何在Python中实现这个功能?
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")
当前回答
这就是我对LeetCode问题706的解决方案:
一个哈希映射类，有三个方法:get、put和remove
class Item:
def __init__(self, key, value):
self.key = key
self.value = value
self.next = None
class MyHashMap:
def __init__(self, size=100):
self.items = [None] * size
self.size = size
def _get_index(self, key):
return hash(key) & self.size-1
def put(self, key: int, value: int) -> None:
index = self._get_index(key)
item = self.items[index]
if item is None:
self.items[index] = Item(key, value)
else:
if item.key == key:
item.value = value
else:
while True:
if item.key == key:
item.value = value
return
else:
if not item.next:
item.next = Item(key, value)
return
item = item.next
def get(self, key: int) -> int:
index = self._get_index(key)
if self.items[index] is None:
return -1
item = self.items[index]
while True:
if item.key == key:
return item.value
else:
if item.next:
item = item.next
else:
return -1
def remove(self, key: int) -> None:
value = self.get(key)
if value > -1:
index = self._get_index(key)
item = self.items[index]
if item.key == key:
self.items[index] = item.next if item.next else None
return
while True:
if item.next and item.next.key == key:
item.next = item.next.next
return
else:
if item.next:
item = item.next
else:
return
其他回答
streetno = { 1 : "Sachin Tendulkar",
2 : "Dravid",
3 : "Sehwag",
4 : "Laxman",
5 : "Kohli" }
和检索值:
name = streetno.get(3, "default value")
Or
name = streetno[3]
这是用数字作为键，在数字周围加上引号，用字符串作为键。
Python中的字典是实现这一点的最佳方式。我们可以使用给定的<key,value>对创建以下字典:
d = {"1": "Sachin Tendulkar", "2": "Dravid", "3": "Sehwag", "4": "Laxman", "5": "Kohli"}
要提取特定键的值，我们可以直接使用d[key]:
name = d["1"] # The value of name would be "Sachin Tendulkar" here
这就是我对LeetCode问题706的解决方案:
一个哈希映射类，有三个方法:get、put和remove
class Item:
def __init__(self, key, value):
self.key = key
self.value = value
self.next = None
class MyHashMap:
def __init__(self, size=100):
self.items = [None] * size
self.size = size
def _get_index(self, key):
return hash(key) & self.size-1
def put(self, key: int, value: int) -> None:
index = self._get_index(key)
item = self.items[index]
if item is None:
self.items[index] = Item(key, value)
else:
if item.key == key:
item.value = value
else:
while True:
if item.key == key:
item.value = value
return
else:
if not item.next:
item.next = Item(key, value)
return
item = item.next
def get(self, key: int) -> int:
index = self._get_index(key)
if self.items[index] is None:
return -1
item = self.items[index]
while True:
if item.key == key:
return item.value
else:
if item.next:
item = item.next
else:
return -1
def remove(self, key: int) -> None:
value = self.get(key)
if value > -1:
index = self._get_index(key)
item = self.items[index]
if item.key == key:
self.items[index] = item.next if item.next else None
return
while True:
if item.next and item.next.key == key:
item.next = item.next.next
return
else:
if item.next:
item = item.next
else:
return
你所需要的(在最初问问题的时候)只是一个暗示。这里有一个提示:在Python中，您可以使用字典。
哈希映射是Python中内置的，它们被称为字典:
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"
有关更多信息，如内置方法等，请参阅文档。它们很棒，在Python程序中非常常见(这并不奇怪)。
