{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "生活中编码无处不在，如身份证号、银行卡号、邮政编 码、学籍号、车牌号及条形码、二维码等，都是按照一定的规则产生的编码。"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "__下面的代码定义了十进制转化为二进制的功能，动手验证一下吧！__"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "请输入一个数字: 9\n"
     ]
    },
    {
     "data": {
      "text/plain": [
       "'1001'"
      ]
     },
     "execution_count": 1,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "def my_bin(num):\n",
    "    la = []\n",
    "    if num < 0:\n",
    "        return '-' + my_bin(abs(num))\n",
    "    while True:\n",
    "        num, remainder = divmod(num, 2)\n",
    "        la.append(str(remainder))\n",
    "        if num == 0:\n",
    "            return ''.join(la[::-1])\n",
    "c = input(\"请输入一个数字: \")\n",
    "my_bin(int(c))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
  "kernelspec": {
   "display_name": "Python 3",
   "language": "python",
   "name": "python3"
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  "language_info": {
   "codemirror_mode": {
    "name": "ipython",
    "version": 3
   },
   "file_extension": ".py",
   "mimetype": "text/x-python",
   "name": "python",
   "nbconvert_exporter": "python",
   "pygments_lexer": "ipython3",
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