{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# dict的创建方法\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**直接通过花括号括起来，里面存放键值对，key:value，用逗号隔开**\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'name': 'lsm', 'age': 30, 'job': 'teacher'}\n"
     ]
    }
   ],
   "source": [
    "dict1={'name':'lsm','age':30,'job':'teacher'} #dict是无序的\n",
    "print(dict1)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**通过dict函数创建一个字典**dict函数的参数有三种方式<br/>\n",
    "**1、 mapping,一个mapping对象（key,value）对**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{1: 'one', 2: 'tow', 3: 'three'}\n"
     ]
    }
   ],
   "source": [
    "dict2=dict(((1,'one'),(2,'tow'),(3,'three')))\n",
    "print(dict2)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**2、可迭代对象 list,tuple**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'name': 'cxf', 'age': 28, 'job': 'economic'}\n"
     ]
    }
   ],
   "source": [
    "list1=[('name','cxf'),('age',28),('job','economic')]\n",
    "dict3=dict(list1)\n",
    "print(dict3)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**3、关键字参数**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'a': 'java', 'b': 'python', 'c': 'javascript'}\n"
     ]
    }
   ],
   "source": [
    "dict4=dict(a='java',b='python',c='javascript')\n",
    "print(dict4)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**4、得到字典的键列表**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 5,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'name': 'lsm', 'age': 30, 'job': 'teacher'}"
      ]
     },
     "execution_count": 5,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "dict1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "dict_keys(['name', 'age', 'job'])"
      ]
     },
     "execution_count": 6,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "dict1.keys()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "['name', 'age', 'job']\n"
     ]
    }
   ],
   "source": [
    "print(list(dict1.keys()))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**5、得到字典的项，一个键值对的元组列表**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 8,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "dict_items([('name', 'lsm'), ('age', 30), ('job', 'teacher')])\n"
     ]
    }
   ],
   "source": [
    "print(dict1.items())"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**6、获取输入的key对应的value**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'name': 'lsm', 'age': 30, 'job': 'teacher'}"
      ]
     },
     "execution_count": 10,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "dict1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "lsm\n",
      "None\n",
      "XXXXXXXXXXXXXX\n"
     ]
    }
   ],
   "source": [
    "print(dict1.get('name'))\n",
    "print(dict1.get('city')) #不存在则返回None\n",
    "print(dict1.get('interest','XXXXXXXXXXXXXX')) #如果有传入第二个参数则在key不存在的时候返回第二个参数的内容"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**7、删除key对应的项，返回该项**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'name': 'lsm', 'job': 'teacher'}\n",
      "该项不存在\n"
     ]
    }
   ],
   "source": [
    "dict1.pop('age')\n",
    "print(dict1)\n",
    "print(dict1.pop('class','该项不存在')) #这种方式比较好，如果key不存在则会返回自定义提示内容"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**8、删除最后一项**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{'name': 'lsm', 'age': 30, 'job': 'teacher'}"
      ]
     },
     "execution_count": 17,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "dict1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'name': 'lsm', 'age': 30}\n"
     ]
    }
   ],
   "source": [
    "dict1.popitem()\n",
    "print(dict1)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**9、清空字典**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{}"
      ]
     },
     "execution_count": 20,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "dict1.clear()\n",
    "dict1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "{1: 'one', 2: 'tow', 3: 'three'}"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "dict2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{1: 'one', 2: 'tow', 3: 'three'}\n"
     ]
    }
   ],
   "source": [
    "another_dict=dict2 #创建另外一个字典指向dict2所指向的字典\n",
    "print(another_dict)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "dict2={} #采用这种方式也可以将字典元素置为空，但实际上只是将dict2重新指向了一个空的字典，原来字典的元素还存在内存中，这是一个不保险的方法\n",
    "print(another_dict) #字典的元素还是存在的\n",
    "print(dict2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "another_dict.clear() #如果用clear方法则会将字典元素从内存清空\n",
    "print(another_dict)\n",
    "\n",
    "print(dict1)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**10、更新列表**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 24,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'name': 'lsm', 'age': 30, 'job': 'teacher'}\n"
     ]
    }
   ],
   "source": [
    "dict1={'name':'lsm','age':30,'job':'teacher'} #dict是无序的\n",
    "print(dict1)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "增量更新"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 25,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'name': 'llx', 'age': 20, 'job': 'teacher', 'interest': 'play', 'city': 'amoi'}\n",
      "{'name': 'llx', 'age': 20, 'job': 'engineer', 'interest': 'play', 'city': 'amoi', 'school': 'xiamen university'}\n"
     ]
    }
   ],
   "source": [
    "update_list=[('name','llx'),('age',20),('interest','play'),('city','amoi')] #可以是一个列表\n",
    "update_dict={'job':'engineer','school':'xiamen university'} #更可以是一个字典\n",
    "dict1.update(update_list)\n",
    "print(dict1)\n",
    "dict1.update(update_dict)\n",
    "print(dict1)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**用关键字更新字典**\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{'name': 'llx', 'age': 20, 'job': 'engineer', 'interest': 'play', 'city': 'amoi', 'school': 'xiamen university', 'skill': 'python'}\n"
     ]
    }
   ],
   "source": [
    "dict1.update(skill='python')\n",
    "print(dict1)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**11、字典的拷贝**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {},
   "outputs": [],
   "source": [
    "copy_dict1=dict1.copy()\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "(2546199132056, 2546199130976)"
      ]
     },
     "execution_count": 28,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "id(dict1),id(copy_dict1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 7,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "1315575443888"
      ]
     },
     "execution_count": 7,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "point_dict1=dict1 #用另外一个变量指向dict1\n",
    "id(point_dict1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "**12、fromkeys,第一个参数是一个序列，第二个参数是value值，会生成一个以序列为key，值全部为value的字典**"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 10,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "{0: ['good', 'bad'], 1: ['good', 'bad']}\n"
     ]
    }
   ],
   "source": [
    "dict5=dict()\n",
    "dict5=dict5.fromkeys(range(2),['good','bad'])\n",
    "print(dict5)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Bob\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "{'age': 14, 'sex': 'male'}"
      ]
     },
     "execution_count": 11,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "D= {'name': 'Bob', 'age': 14, 'sex': 'male'}\n",
    "pop_obj=D.pop('name')\n",
    "print(pop_obj)\n",
    "D"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Bob\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "{'age': 14, 'sex': 'male'}"
      ]
     },
     "execution_count": 12,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "D= {'name': 'Bob', 'age': 14, 'sex': 'male'}\n",
    "pop_obj=D.pop('name','age')\n",
    "print(pop_obj)\n",
    "D"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "metadata": {},
   "outputs": [],
   "source": [
    "D = {'name': 'Bob', 'age': 14, 'sex': 'male'}\n",
    "key_list=['name','age']"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "metadata": {},
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "unhashable type: 'list'",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-20-449aae5c4334>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[0mpop_obj\u001b[0m \u001b[1;33m=\u001b[0m \u001b[0mD\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mpop\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mkey_list\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m: unhashable type: 'list'"
     ]
    }
   ],
   "source": [
    "pop_obj = D.pop(key_list)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Bob\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "{'name': 'Bob', 'age': 14, 'sex': 'male'}"
      ]
     },
     "execution_count": 21,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "print(pop_obj)\n",
    "D"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  },
  {
   "cell_type": "code",
   "execution_count": 23,
   "metadata": {},
   "outputs": [
    {
     "ename": "TypeError",
     "evalue": "unhashable type: 'dict'",
     "output_type": "error",
     "traceback": [
      "\u001b[1;31m---------------------------------------------------------------------------\u001b[0m",
      "\u001b[1;31mTypeError\u001b[0m                                 Traceback (most recent call last)",
      "\u001b[1;32m<ipython-input-23-5a0f412e5042>\u001b[0m in \u001b[0;36m<module>\u001b[1;34m()\u001b[0m\n\u001b[0;32m      2\u001b[0m \u001b[0mD\u001b[0m\u001b[1;33m=\u001b[0m \u001b[1;33m{\u001b[0m\u001b[1;34m'name'\u001b[0m\u001b[1;33m:\u001b[0m \u001b[1;34m'Bob'\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;34m'age'\u001b[0m\u001b[1;33m:\u001b[0m \u001b[1;36m14\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;34m'sex'\u001b[0m\u001b[1;33m:\u001b[0m \u001b[1;34m'male'\u001b[0m\u001b[1;33m}\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m      3\u001b[0m \u001b[0mkey_dict\u001b[0m\u001b[1;33m=\u001b[0m\u001b[1;33m{\u001b[0m\u001b[1;34m'name'\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;36m0\u001b[0m\u001b[1;33m,\u001b[0m\u001b[1;34m'age'\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;36m0\u001b[0m\u001b[1;33m}\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 4\u001b[1;33m \u001b[0mpop_obj\u001b[0m\u001b[1;33m=\u001b[0m\u001b[0mD\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mpop\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mkey_dict\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m      5\u001b[0m \u001b[0mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mpop_obj\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m      6\u001b[0m \u001b[0mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mD\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n",
      "\u001b[1;31mTypeError\u001b[0m: unhashable type: 'dict'"
     ]
    }
   ],
   "source": [
    "#用list装key会raise TypeError，试试用dict装\n",
    "D= {'name': 'Bob', 'age': 14, 'sex': 'male'}\n",
    "key_dict={'name':0,'age':0}\n",
    "pop_obj=D.pop(key_dict)\n",
    "print(pop_obj)\n",
    "print(D)\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
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