{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# 函式 - Functions"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "id": "DfxkgDhjseNg"
   },
   "source": [
    "本章節內容大綱\n",
    "* [函式 Function](#函式-Function)\n",
    "* [匿名函式 Lambda Function](#匿名函式-Lambda-Function)\n",
    "* [產生器 Generator](#產生器-Generator)\n",
    "* [星號，args 和 kargs](#星號-args-kargs)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "id": "c75Y792JseNh"
   },
   "source": [
    "## 函式 Function"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "DIghQmm5seNh",
    "outputId": "11697eb8-0cea-4d15-d25e-e648c5d30040"
   },
   "outputs": [],
   "source": [
    "'''\n",
    "    def function_name(parameters):\n",
    "        'function docstring'\n",
    "        do something\n",
    "        return something\n",
    "'''"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "vXcFP5lNseNj"
   },
   "outputs": [],
   "source": [
    "# 什麼事都沒有做的 function\n",
    "def do_nothing():\n",
    "    pass"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "do_nothing()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "I0z4IVPjseNj"
   },
   "outputs": [],
   "source": [
    "# 沒有參數/回傳值的，純粹執行一些事情的 function\n",
    "def say_hello():\n",
    "    print(f'hello!')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "Mj0BVefKseNj",
    "outputId": "f6e2be01-5a6a-4832-90e6-c0664567ae0f"
   },
   "outputs": [],
   "source": [
    "say_hello()\n",
    "say_hello()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# 沒有參數，但有回傳值的 function\n",
    "def three():\n",
    "    return 3"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "h9vjWKOOseNk",
    "outputId": "9bfb6420-4729-4737-81aa-775266cee61e"
   },
   "outputs": [],
   "source": [
    "print(5 + three())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# 有參數/回傳值的 function\n",
    "def add(a, b):\n",
    "    print(f'a = {a}, b = {b}')\n",
    "    return a + b"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "9fDZEClEseNl",
    "outputId": "06ff637f-d4af-41e7-a9f7-1749c0164c01"
   },
   "outputs": [],
   "source": [
    "print(add(10, 8))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "id": "AUNa91SoseNm"
   },
   "source": [
    "## 匿名函式 Lambda Function"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "'''\n",
    "function_name = lambda input : calculation or output\n",
    "'''\n",
    "\n",
    "f = lambda x: x ** 2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "print(f(4))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "f = lambda x, y: x**2 + 2*x*y + y**2"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "print(f(5,5))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "SFvJrSqRseNm",
    "outputId": "6371e929-d747-471b-9505-d9862dfbbc3a"
   },
   "outputs": [],
   "source": [
    "f = lambda x: [i*i for i in range(0, x+1)]"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "sg43LMkSseNn",
    "outputId": "21d0814b-99af-43a8-abfb-91b434537563"
   },
   "outputs": [],
   "source": [
    "print(f(10))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "f = lambda s: s.upper() + '!'"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "print(f('hello'))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "id": "xWjpdhh8seNn"
   },
   "source": [
    "## 產生器 Generator"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def simpleFunction():\n",
    "    return 1  # return 完 記憶會清空，下次呼叫此函式時會從頭跑\n",
    "    return 2  # 所以這行永遠不會被執行到"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "print(simpleFunction())\n",
    "print(simpleFunction())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def simpleGenerator():\n",
    "    yield 1  # yield 完 記憶不會清空，下次呼叫此函式時會從下一行開始跑\n",
    "    yield 2  # 第二次進入此函式時就會從這裡開始"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "print(simpleGenerator())"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "g1 = simpleGenerator()\n",
    "print(next(g1))\n",
    "print(next(g1))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "zWMOMkwOseNn"
   },
   "outputs": [],
   "source": [
    "def randomGenerator(N):\n",
    "\n",
    "    import random\n",
    "\n",
    "    L = [i + 1 for i in range(N)]\n",
    "    random.shuffle(L)\n",
    "\n",
    "    for v in L:\n",
    "        yield v"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "R = randomGenerator(5)\n",
    "for i in range(5):\n",
    "    print(next(R))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "print(next(R))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def randomGenerator(N):\n",
    "\n",
    "    import random\n",
    "\n",
    "    while True:\n",
    "\n",
    "        L = [i + 1 for i in range(N)]\n",
    "        random.shuffle(L)\n",
    "\n",
    "        for v in L:\n",
    "            yield v"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "R = randomGenerator(5)\n",
    "for i in range(50):\n",
    "    print(next(R))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "SyzbOn2dseNo"
   },
   "outputs": [],
   "source": [
    "def myRange(start=0, end=0, step=1):\n",
    "    current = start\n",
    "    while current < end:\n",
    "        yield current\n",
    "        current += step"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "R = myRange(0, 10, 2)\n",
    "for value in R:\n",
    "    print(value)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "id": "fymwj8_RseNo"
   },
   "source": [
    "## 星號 args kargs"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def argsTest(*args):\n",
    "    print(f'Parameter count: {len(args)}')\n",
    "    print(args)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "argsTest(1,  3,  5)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def kargsTest(*args, **kargs):\n",
    "    print(f'Parameter count: {len(args)}')\n",
    "    print(args)\n",
    "    print(f'Named Parameter count: {len(kargs)}')\n",
    "    print(kargs)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "kargsTest(1, 2, 3, 4, 5, a='1', b=2, c=3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "YcEnSFdEseNo"
   },
   "outputs": [],
   "source": [
    "def myRange(*args):\n",
    "    start, end, step = 0, 0, 1\n",
    "    if len(args) == 1:\n",
    "        end = args[0]\n",
    "    elif len(args) == 2:\n",
    "        start, end = args[0], args[1]\n",
    "    elif len(args) == 3:\n",
    "        start, end, step = args[0], args[1], args[2]\n",
    "    current = start\n",
    "    while current < end:\n",
    "        yield current\n",
    "        current += step"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for value in myRange(10):\n",
    "    print(value)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for value in myRange(2, 10):\n",
    "    print(value)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "for value in myRange(1, 10, 3):\n",
    "    print(value)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "# 練習：輸入一個數字，找出小於該數字的所有質數\n",
    "def find_prime(x):\n",
    "\n",
    "    prime = [True] * (x + 1)\n",
    "    prime[0] = False\n",
    "    prime[1] = False\n",
    "\n",
    "    i = 2\n",
    "    while i < x:\n",
    "\n",
    "        while i < x and prime[i] == False:\n",
    "            i += 1\n",
    "\n",
    "        for value in range(2*i, x+1, i):\n",
    "            prime[value] = False\n",
    "\n",
    "        i += 1\n",
    "\n",
    "    return [index for index, value in enumerate(prime) if value == True]\n",
    "\n",
    "\n",
    "print(find_prime(1))\n",
    "print(find_prime(2))\n",
    "print(find_prime(5))\n",
    "print(find_prime(7))\n",
    "print(find_prime(11))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "\n",
    "\n",
    "\n",
    "---\n",
    "\n",
    "\n",
    "\n",
    "\n",
    "\n",
    "\n",
    "\n",
    "\n",
    "\n",
    "\n",
    "\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Quiz"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "YZZP9ev2seNo"
   },
   "outputs": [],
   "source": [
    "# quiz1: 實作一個 lambda function，把輸入(數字）平方之後加上 5 回傳。"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "v_dje-IKseNp"
   },
   "outputs": [],
   "source": [
    "# quiz2: 實作一個 function，輸入寬 (w) 及長 (l) 後印出如附圖所示的鉛筆形狀。\n",
    "\n",
    "# |******\n",
    "# |*******\n",
    "# w********\n",
    "# |*******\n",
    "# |******\n",
    "#  --l--\n",
    "\n",
    "# e.g. \n",
    "# pencil(5, 6) 會印出\n",
    "# *******\n",
    "# ********\n",
    "# *********\n",
    "# ********\n",
    "# *******\n",
    "\n",
    "def pencil(w, l):\n",
    "    pass"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "vjZxKfg-seNp"
   },
   "outputs": [],
   "source": [
    "# quiz3: 建構一個 費式數列 的 generator\n",
    "\n",
    "# 使用 next() 的時候\n",
    "# 第一次 yield 1\n",
    "# 第二次 yield 1\n",
    "# 第三次 yield 2\n",
    "# 第四次 yield 3\n",
    "# 第五次 yield 5\n",
    "# ... 以此類推\n",
    "\n",
    "def fib_generator():\n",
    "    # your code here"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "id": "jMtxUBvuseNp"
   },
   "outputs": [],
   "source": [
    "# 可以使用此段程式驗證你的 generator 有沒有成功\n",
    "\n",
    "f = fib_generator()\n",
    "for i in range(10):\n",
    "    print(next(f))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": []
  }
 ],
 "metadata": {
  "colab": {
   "name": "5 Functions.ipynb",
   "provenance": []
  },
  "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": "3.7.6"
  },
  "vscode": {
   "interpreter": {
    "hash": "f2c5ff1dcfb7037f8bc8783b5d7cd749bee6b69d77e75d46cb9007d97777ae49"
   }
  }
 },
 "nbformat": 4,
 "nbformat_minor": 4
}