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update by first online course

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Chuanyu Xue
2021-07-21 11:09:19 +08:00
parent bfd5bf0f33
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1. Python 安装及基本语法.ipynb
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@@ -197,64 +197,31 @@
},
{
"cell_type": "code",
"execution_count": 6,
"execution_count": null,
"source": [
"## 2 表示 整数(integer) 2\n",
"type(2)"
],
"outputs": [
{
"output_type": "execute_result",
"data": {
"text/plain": [
"int"
]
},
"metadata": {},
"execution_count": 6
}
],
"outputs": [],
"metadata": {}
},
{
"cell_type": "code",
"execution_count": 7,
"execution_count": null,
"source": [
"## 2.333 与 1e-9 表示对应浮点数(float)\n",
"type(2.33)"
],
"outputs": [
{
"output_type": "execute_result",
"data": {
"text/plain": [
"float"
]
},
"metadata": {},
"execution_count": 7
}
],
"outputs": [],
"metadata": {}
},
{
"cell_type": "code",
"execution_count": 8,
"execution_count": null,
"source": [
"type(1e-9)"
],
"outputs": [
{
"output_type": "execute_result",
"data": {
"text/plain": [
"float"
]
},
"metadata": {},
"execution_count": 8
}
],
"outputs": [],
"metadata": {}
},
{
@@ -281,7 +248,7 @@
},
{
"cell_type": "code",
"execution_count": 24,
"execution_count": 11,
"source": [
"## True 代表逻辑值(Boolen)\n",
"type(True)"
@@ -295,7 +262,28 @@
]
},
"metadata": {},
"execution_count": 24
"execution_count": 11
}
],
"metadata": {}
},
{
"cell_type": "code",
"execution_count": 12,
"source": [
"\n",
"type(False)"
],
"outputs": [
{
"output_type": "execute_result",
"data": {
"text/plain": [
"bool"
]
},
"metadata": {},
"execution_count": 12
}
],
"metadata": {}
@@ -312,13 +300,13 @@
"source": [
"与常量相反，变量可以存储不同的值以表示不同的内容，并且它的值可以被更改。变量通过赋值符号 = 创建，例如variable = 1。\n",
"\n",
"注意变量存在命名规范。变量的第一个字符必须是字母，其余部分由下划线或数字组成，且区分大小写。例如 a_123 可以是一个变量，123_a 不可以是一个变量，A_123 与 a_123 表示两个不同变量。"
"注意变量存在命名规范。变量的第一个字符必须是字母或下划线，其余部分由下划线或数字组成，且区分大小写。例如 a_123 可以是一个变量，123_a 不可以是一个变量，A_123 与 a_123 表示两个不同变量。"
],
"metadata": {}
},
{
"cell_type": "code",
"execution_count": 14,
"execution_count": 13,
"source": [
"## 创建名为 variable 的变量存储一个 整数 值\n",
"\n",
@@ -334,7 +322,7 @@
]
},
"metadata": {},
"execution_count": 14
"execution_count": 13
}
],
"metadata": {}
@@ -364,7 +352,7 @@
},
{
"cell_type": "code",
"execution_count": 19,
"execution_count": 16,
"source": [
"## 常量的值无法修改 触发语法错误提示\n",
"\n",
@@ -374,9 +362,9 @@
{
"output_type": "error",
"ename": "SyntaxError",
"evalue": "cannot assign to literal (<ipython-input-19-11df37b38908>, line 3)",
"evalue": "cannot assign to literal (<ipython-input-16-11df37b38908>, line 3)",
"traceback": [
"\u001b[0;36m File \u001b[0;32m\"<ipython-input-19-11df37b38908>\"\u001b[0;36m, line \u001b[0;32m3\u001b[0m\n\u001b[0;31m 2.33 = 2.55\u001b[0m\n\u001b[0m ^\u001b[0m\n\u001b[0;31mSyntaxError\u001b[0m\u001b[0;31m:\u001b[0m cannot assign to literal\n"
"\u001b[0;36m File \u001b[0;32m\"<ipython-input-16-11df37b38908>\"\u001b[0;36m, line \u001b[0;32m3\u001b[0m\n\u001b[0;31m 2.33 = 2.55\u001b[0m\n\u001b[0m ^\u001b[0m\n\u001b[0;31mSyntaxError\u001b[0m\u001b[0;31m:\u001b[0m cannot assign to literal\n"
]
}
],
@@ -384,7 +372,7 @@
},
{
"cell_type": "code",
"execution_count": 20,
"execution_count": 17,
"source": [
"## 变量的命名不满足规范 触发语法错误提示\n",
"\n",
@@ -394,9 +382,9 @@
{
"output_type": "error",
"ename": "SyntaxError",
"evalue": "invalid decimal literal (<ipython-input-20-594a879f97d7>, line 3)",
"evalue": "invalid decimal literal (<ipython-input-17-bb1ef621bcb6>, line 3)",
"traceback": [
"\u001b[0;36m File \u001b[0;32m\"<ipython-input-20-594a879f97d7>\"\u001b[0;36m, line \u001b[0;32m3\u001b[0m\n\u001b[0;31m 123_a = 1\u001b[0m\n\u001b[0m ^\u001b[0m\n\u001b[0;31mSyntaxError\u001b[0m\u001b[0;31m:\u001b[0m invalid decimal literal\n"
"\u001b[0;36m File \u001b[0;32m\"<ipython-input-17-bb1ef621bcb6>\"\u001b[0;36m, line \u001b[0;32m3\u001b[0m\n\u001b[0;31m 123_a = 1\u001b[0m\n\u001b[0m ^\u001b[0m\n\u001b[0;31mSyntaxError\u001b[0m\u001b[0;31m:\u001b[0m invalid decimal literal\n"
]
}
],
@@ -473,14 +461,14 @@
"例如：\n",
"\n",
" 输入：2,3,7,11,15, target = 13\n",
" 输出：2,7\n",
" 解释：第0个数和第2个数的和为13 （注：编程时我们习惯从第0个开始数）"
" 输出：2,11\n",
" 解释：第0个数和第3个数的和为13 （注：编程时我们习惯从第0个开始数）"
],
"metadata": {}
},
{
"cell_type": "code",
"execution_count": 36,
"execution_count": 29,
"source": [
"## 尝试求解，改变 a b 的值依次两两尝试，直到 a + b = target\n",
"\n",
@@ -498,14 +486,14 @@
]
},
"metadata": {},
"execution_count": 36
"execution_count": 29
}
],
"metadata": {}
},
{
"cell_type": "code",
"execution_count": 37,
"execution_count": 30,
"source": [
"a = 2\n",
"b = 7\n",
@@ -520,14 +508,14 @@
]
},
"metadata": {},
"execution_count": 37
"execution_count": 30
}
],
"metadata": {}
},
{
"cell_type": "code",
"execution_count": 38,
"execution_count": 31,
"source": [
"a = 2\n",
"b = 11\n",
@@ -542,14 +530,14 @@
]
},
"metadata": {},
"execution_count": 38
"execution_count": 31
}
],
"metadata": {}
},
{
"cell_type": "code",
"execution_count": 39,
"execution_count": 32,
"source": [
"a,b"
],
@@ -562,7 +550,7 @@
]
},
"metadata": {},
"execution_count": 39
"execution_count": 32
}
],
"metadata": {}
@@ -601,7 +589,7 @@
},
{
"cell_type": "code",
"execution_count": 62,
"execution_count": 33,
"source": [
"## 自动输出最后的 target\n",
"\n",
@@ -617,14 +605,14 @@
]
},
"metadata": {},
"execution_count": 62
"execution_count": 33
}
],
"metadata": {}
},
{
"cell_type": "code",
"execution_count": 63,
"execution_count": 34,
"source": [
"## 自动输出最后的 variable\n",
"\n",
@@ -640,7 +628,7 @@
]
},
"metadata": {},
"execution_count": 63
"execution_count": 34
}
],
"metadata": {}
@@ -654,7 +642,7 @@
},
{
"cell_type": "code",
"execution_count": 65,
"execution_count": 36,
"source": [
"## num1，num2 是输入的参数， return 后面的 a+b==target 是函数的结果\n",
"\n",
@@ -686,7 +674,7 @@
},
{
"cell_type": "code",
"execution_count": 66,
"execution_count": 37,
"source": [
"## 这里 2,3,13 是实参，函数返回结果 False\n",
"\n",
@@ -725,11 +713,11 @@
},
{
"cell_type": "code",
"execution_count": 67,
"execution_count": 38,
"source": [
"## 尝试在函数外部使用变量 num1，系统报错 num1 未定义\n",
"\n",
"num1"
"print(num1)"
],
"outputs": [
{
@@ -739,7 +727,7 @@
"traceback": [
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
"\u001b[0;31mNameError\u001b[0m Traceback (most recent call last)",
"\u001b[0;32m<ipython-input-67-480f0d231548>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[1;32m 1\u001b[0m \u001b[0;31m## 尝试在函数外部使用变量 num1，系统报错 num1 未定义\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 2\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 3\u001b[0;31m \u001b[0mnum1\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
"\u001b[0;32m<ipython-input-38-9b7c7bff9b5d>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m\u001b[0m\n\u001b[1;32m 1\u001b[0m \u001b[0;31m## 尝试在函数外部使用变量 num1，系统报错 num1 未定义\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 2\u001b[0m \u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 3\u001b[0;31m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mnum1\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
"\u001b[0;31mNameError\u001b[0m: name 'num1' is not defined"
]
}
@@ -748,7 +736,7 @@
},
{
"cell_type": "code",
"execution_count": 68,
"execution_count": 39,
"source": [
"## 尝试重新定义函数 check_sum, 此时函数参数中已不存在target\n",
"\n",
@@ -763,7 +751,7 @@
},
{
"cell_type": "code",
"execution_count": 71,
"execution_count": 40,
"source": [
"print(check_sum(2, 3))\n",
"\n",
@@ -801,7 +789,7 @@
{
"cell_type": "markdown",
"source": [
"通过控制符与函数，我们可以操作变量完成简单的任务。然而本质上我们还在把 Python 当作一个计算器使用，而不是一个可以实现自动化的编程语言，每行代码按照自上而下的顺序依次执行。通过控制流，我们可以让程序自动判断逻辑，自动跳转到某个位置，从而实现自动控制。\n",
"通过运算符与函数，我们可以操作变量完成简单的任务。然而本质上我们还在把 Python 当作一个计算器使用，而不是一个可以实现自动化的编程语言，每行代码按照自上而下的顺序依次执行。通过控制流，我们可以让程序自动判断逻辑，自动跳转到某个位置，从而实现自动控制。\n",
"\n",
"控制流中涉及几个关键字：\n",
"\n",
@@ -831,7 +819,7 @@
},
{
"cell_type": "code",
"execution_count": 76,
"execution_count": 41,
"source": [
"## while 循环语句样例\n",
"\n",
@@ -886,7 +874,7 @@
},
{
"cell_type": "code",
"execution_count": 77,
"execution_count": 42,
"source": [
"## for-in 循环语句样例\n",
"\n",
@@ -917,7 +905,7 @@
},
{
"cell_type": "code",
"execution_count": 81,
"execution_count": 43,
"source": [
"## 依次迭代元素 a，一共迭代 5 次\n",
"for a in [2,3,7,11,15]:\n",
@@ -986,6 +974,13 @@
],
"metadata": {}
},
{
"cell_type": "markdown",
"source": [
"> 女朋友说，下班回来带一个西瓜。如果看到番茄，就买两个。最后程序员买回来两个西瓜。"
],
"metadata": {}
},
{
"cell_type": "markdown",
"source": [
@@ -997,7 +992,7 @@
},
{
"cell_type": "code",
"execution_count": 85,
"execution_count": 44,
"source": [
"## 加入 if-else 逻辑语句\n",
"\n",
@@ -1046,7 +1041,7 @@
},
{
"cell_type": "code",
"execution_count": 87,
"execution_count": 45,
"source": [
"## 添加 break 停止语句\n",
"\n",
@@ -1092,7 +1087,7 @@
},
{
"cell_type": "code",
"execution_count": 89,
"execution_count": 46,
"source": [
"for a in [2,3,7,11,15]:\n",
" print(a)\n",
@@ -1150,7 +1145,7 @@
},
{
"cell_type": "code",
"execution_count": 108,
"execution_count": null,
"source": [
"## 定义阶乘函数，用于排列组合中\n",
"def multiple(x):\n",
@@ -1165,7 +1160,7 @@
},
{
"cell_type": "code",
"execution_count": 110,
"execution_count": null,
"source": [
"## 定义二项分布计算函数\n",
"def p_xk(k):\n",
@@ -1181,7 +1176,7 @@
},
{
"cell_type": "code",
"execution_count": 117,
"execution_count": null,
"source": [
"## 根据二项分布计算概率\n",
"k = 0\n",
@@ -1189,35 +1184,7 @@
" print('P{ X =',k,'} = ', p_xk(k))\n",
" k = k + 1"
],
"outputs": [
{
"output_type": "stream",
"name": "stdout",
"text": [
"P{ X = 0 } = 0.011529215046068483\n",
"P{ X = 1 } = 0.05764607523034242\n",
"P{ X = 2 } = 0.13690942867206327\n",
"P{ X = 3 } = 0.20536414300809488\n",
"P{ X = 4 } = 0.21819940194610074\n",
"P{ X = 5 } = 0.17455952155688062\n",
"P{ X = 6 } = 0.10909970097305038\n",
"P{ X = 7 } = 0.054549850486525185\n",
"P{ X = 8 } = 0.022160876760150862\n",
"P{ X = 9 } = 0.007386958920050286\n",
"P{ X = 10 } = 0.0020314137030138287\n",
"P{ X = 11 } = 0.00046168493250314287\n",
"P{ X = 12 } = 8.65659248443393e-05\n",
"P{ X = 13 } = 1.3317834591436813e-05\n",
"P{ X = 14 } = 1.6647293239296018e-06\n",
"P{ X = 15 } = 1.6647293239296019e-07\n",
"P{ X = 16 } = 1.3005697843200012e-08\n",
"P{ X = 17 } = 7.65041049600001e-10\n",
"P{ X = 18 } = 3.1876710400000044e-11\n",
"P{ X = 19 } = 8.38860800000001e-13\n",
"P{ X = 20 } = 1.0485760000000012e-14\n"
]
}
],
"outputs": [],
"metadata": {}
}
],