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103 lines
2.9 KiB
103 lines
2.9 KiB
{
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"cells": [
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## 数值数据的编码 \n",
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"__数值数据是一类常见数据，是可用于算术运算的具体数\n",
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"值。例如，鸟的数量是 21 只，这个数值数据在计算机中是如 何表示的呢?\n",
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"计算机中的数值数据是以补码的方式表示的，以十进制 数 +21 和 -21 的 8 位编码为例，它们的二进制数、原码、反 码和补码分别如下。__"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"$(+21)_{10}=(+10101)_2$ $(-21)_{10}=(-10101)_2$\n",
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"\n",
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" $[+10101]_{原}= 00010101 $ \n",
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" \n",
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" $[+10101] 反= 00010101 $\n",
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" \n",
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" $[+10101] _{补}= 00010101$\n",
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" \n",
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"$[-10101]_{原}= 10010101 $\n",
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"\n",
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"$[-10101]_{反}= 11101010 $\n",
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"\n",
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"$[-10101]_{补}= 11101011$"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"## 文本数据的编码\n",
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"__记录鸟类活动时需要记录鸟的名称，例如灰眶雀鹛的学\n",
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"名是 Alcippe Morrisonia。对这些由字母构成的数据，计算机 是如何存储和表示的呢?\n",
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"字母、数字、标点符号等，称为西文字符。计算机在存储 和处理这些西文字符时，需要为每个字符规定一个由 0 和 1 组成的代码。目前，国际上普遍采用的西文字符编码标准是 ASCII 码(American Standard Code for Information Interchange， 美国标准信息交换代码)。__"
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]
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},
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{
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"cell_type": "markdown",
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"metadata": {},
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"source": [
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"__下面的代码块完成了字符与ASCII码之间的编码转化，块运行代码，动手验证一下吧！__"
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]
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},
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{
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"cell_type": "code",
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"execution_count": 1,
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"metadata": {},
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"outputs": [
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{
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"name": "stdout",
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"output_type": "stream",
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"text": [
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"请输入一个字符: 4\n",
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"请输入一个ASCII码: 5\n",
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"4 的ASCII 码为 52\n",
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"5 对应的字符为 \u0005\n"
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]
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}
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],
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"source": [
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"c = input(\"请输入一个字符: \")\n",
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" \n",
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"# 用户输入ASCII码，并将输入的数字转为整型\n",
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"a = int(input(\"请输入一个ASCII码: \")) \n",
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"print( c + \" 的ASCII 码为\", ord(c))\n",
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"print( a , \" 对应的字符为\", chr(a))"
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]
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},
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{
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"cell_type": "code",
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"execution_count": null,
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"metadata": {},
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"outputs": [],
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"source": []
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}
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],
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"metadata": {
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"kernelspec": {
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"display_name": "Python 3",
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"language": "python",
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"name": "python3"
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},
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"language_info": {
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"codemirror_mode": {
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"name": "ipython",
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"version": 3
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},
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"file_extension": ".py",
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"mimetype": "text/x-python",
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"name": "python",
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"nbconvert_exporter": "python",
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"pygments_lexer": "ipython3",
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"version": "3.7.3"
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}
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},
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"nbformat": 4,
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"nbformat_minor": 2
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}
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