笨办法学习python之hashmap

 #!/user/bin/env python
 #-*-coding:utf-8 -*-
 #Author: qinjiaxi
 #初始化aMap列表，把列表num_buckets添加到aMap中，num_bukets用来存hashmap里设置的内容
 def new(num_buckets = 256):
     """Initializes a map with the given number of buckets."""
     aMap = []
     for i in range(0, num_buckets):
         aMap.append([])
     return aMap
 def hash_key(aMap, key):
     """Given a key this will create a number and then convert it to an index for the aMap's buckets."""
     return hash(key) % len(aMap)#利用求余(模除)来获得一个放置key的位置，其中hash()函数是用来获取一个数字或者字符串的哈希值(是一个整数)。
 def get_bucket(aMap, key):
     """Given a key , find the bucket where it would go ."""
     bucket_id = hash_key(aMap, key)
     return  aMap[bucket_id]#通过bucket_id获取bucket
 #使用enumerate()和for循环遍历bucket，用key获取索引、键、值
 def get_slot(aMap, key, default = None):
     """
     Returns the index, key, and value of a slot found in a slot found in a bucket.
     Returns -1, key, and default(None if not set) when not found.
     """
     bucket = get_bucket(aMap, key)
     for i, kv in enumerate(bucket):
         k, v = kv
         if key == k:
             return i, k ,v
     return -1, key, default
 #取值
 def get(aMap, key ,default = None):
     """Gets the value in  a bucket for the given key, or the default."""
     i, k, v = get_slot(aMap, key, default = None)
     return v
 #设置键值对追加到字典中，保证每个key存储一次
 def set(aMap, key, value):
     """Set the key to the value, replacing any existing value."""
     bucket = get_bucket(aMap, key)
     i, k, v = get_slot(aMap, key)
 #如果位置存在就代替
     if i >= 0:
         #the key exists, replace it
         bucket[i] = (key, value)
 #不存在就追加到字典中
     else:
         #the key does not ,append to creat it
         bucket.append((key, value))
 #通过key删除bucket
 def delete(aMap, key):
     """ Deletes the given key from the Map."""
     bucket = get_bucket(aMap, key)
     for i in range(len(bucket)):
         k, v = bucket[i]
         if key == k:
             del bucket[i]
             break
 #调试打印hashmap功能
 def list(aMap):
     """Prints out what's in the Map"""
     for bucket in aMap:
         if bucket:
             for k,v in bucket:
                 print (k, v)