Created
December 5, 2018 03:04
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Associate Array / Map / Dictionary + Hash Function Implements using Python
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{ | |
"cells": [ | |
{ | |
"cell_type": "code", | |
"execution_count": 1, | |
"metadata": {}, | |
"outputs": [], | |
"source": [ | |
"from collections import Iterable\n", | |
"from functools import reduce\n", | |
"\n", | |
"class HashTable(object):\n", | |
" def __init__(self, size=10):\n", | |
" self.size = 10\n", | |
" self.keys = [None] * self.size\n", | |
" self.values = [None] * self.size\n", | |
" \n", | |
" def __repr__(self):\n", | |
" return 'HashTable(size={})'.format(self.size)\n", | |
" \n", | |
" def put(self, key, value): \n", | |
" index = self.hash(key)\n", | |
"\n", | |
" while self.keys[index] is not None: # collision\n", | |
" if self.keys[index] == key: # update\n", | |
" self.values[index] = value \n", | |
" return\n", | |
" index = (index + 1) % self.size # rehash\n", | |
" \n", | |
" self.keys[index] = key\n", | |
" self.values[index] = value\n", | |
" \n", | |
" def get(self, key):\n", | |
" if key in self.keys:\n", | |
" return self.values[self.hash(key)]\n", | |
" return None\n", | |
" \n", | |
" def hash(self, key): \n", | |
" if isinstance(key, Iterable):\n", | |
" sum = reduce(lambda prev, n: prev + ord(n), key, 0)\n", | |
" else:\n", | |
" sum = key\n", | |
" \n", | |
" return sum % self.size" | |
] | |
}, | |
{ | |
"cell_type": "code", | |
"execution_count": 2, | |
"metadata": {}, | |
"outputs": [], | |
"source": [ | |
"h = HashTable()" | |
] | |
}, | |
{ | |
"cell_type": "code", | |
"execution_count": 3, | |
"metadata": {}, | |
"outputs": [], | |
"source": [ | |
"h.put('a', 1)" | |
] | |
}, | |
{ | |
"cell_type": "code", | |
"execution_count": 4, | |
"metadata": {}, | |
"outputs": [ | |
{ | |
"data": { | |
"text/plain": [ | |
"1" | |
] | |
}, | |
"execution_count": 4, | |
"metadata": {}, | |
"output_type": "execute_result" | |
} | |
], | |
"source": [ | |
"h.get('a')" | |
] | |
} | |
], | |
"metadata": { | |
"kernelspec": { | |
"display_name": "Python 3", | |
"language": "python", | |
"name": "python3" | |
}, | |
"language_info": { | |
"codemirror_mode": { | |
"name": "ipython", | |
"version": 3 | |
}, | |
"file_extension": ".py", | |
"mimetype": "text/x-python", | |
"name": "python", | |
"nbconvert_exporter": "python", | |
"pygments_lexer": "ipython3", | |
"version": "3.5.2" | |
} | |
}, | |
"nbformat": 4, | |
"nbformat_minor": 2 | |
} |
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