02_funkcje.ipynb

{
 "cells": [
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "# Język Python\n",
    "## Funkcje i lambdy"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def nwd(a, b):\n",
    "    while b != 0:\n",
    "        a, b = b, a%b\n",
    "    print(\"NWD =\", a)\n",
    "\n",
    "nwd(140, 200)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "print(nwd(140, 200))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def nwd(a, b):\n",
    "    while b != 0:\n",
    "        a, b = b, a%b\n",
    "    return a\n",
    "    \n",
    "nwd(140, 200)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "nwd(200)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "print(1)\n",
    "nwd(1, 2, 3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def say(message, times=1):\n",
    "    print((message + ' ') * times)\n",
    "    \n",
    "say('developers')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "say('developers', 3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "say('developers', times=3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "say(times=3, 'developers')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "say(times=3, message='developers')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "from random import randint\n",
    "\n",
    "def rand():\n",
    "    print(\"Z\")\n",
    "    return randint(1, 100)\n",
    "\n",
    "def print_rand(rand=rand()): #losowanie z przedziału [1;100] (domkniętego)\n",
    "    print(rand)\n",
    "\n",
    "print(\"X\")\n",
    "for i in range(3):\n",
    "    print_rand()\n",
    "print(\"Y\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "def print_rand(rand=None):\n",
    "    if rand is None:\n",
    "        rand = randint(1, 100)\n",
    "    print(rand)\n",
    "\n",
    "for i in range(3):\n",
    "    print_rand()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "source": [
    "## Przeciążanie funkcji"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "source": [
    "#### Nie istnieje"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "def foo():\n",
    "    print(\"Foo\")\n",
    "    \n",
    "def foo(a):\n",
    "    print(\"Foo\", a)\n",
    "    \n",
    "foo()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## Argumenty \\*args, \\**kwargs"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {"slideshow": {
     "slide_type": "subslide"
    }},
   "outputs": [],
   "source": [
    "def say_more(times, *args):\n",
    "    print(args)\n",
    "    print((', '.join(args) + \" | \") * times)\n",
    "\n",
    "say_more(3, 'one', 'two')"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "def say_even_more(*args, **kwargs):\n",
    "    print(args)  # krotka\n",
    "    print(kwargs)  # słownik\n",
    "\n",
    "say_even_more(1, 2, 3, foo=4, bar=5)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def f(a, b, *arguments, c=1, d=4, **keyword_arguments):\n",
    "    print(a, b, c, d, arguments, keyword_arguments)\n",
    "    \n",
    "f(1, 2, 3, 4, 5, 6, c=10)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "def f(a, b, c=1, d=4, *arguments, **keyword_arguments):\n",
    "    print(a, b, c, d, arguments, keyword_arguments)\n",
    "    \n",
    "f(1, 2, 3, 4, 5, 6)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def f(a, b, *arguments, c, d=4, **keyword_arguments):\n",
    "    print(a, b, c, d, arguments, keyword_arguments)\n",
    "    \n",
    "f(1, 2, 3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "def f(a, b, *arguments, c=1, **keyword_arguments, d=4):\n",
    "    print(a, b, c, d, arguments, keyword_arguments)\n",
    "    \n",
    "f(1, 2, 3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def say_even_more(*args, **kwargs):\n",
    "    print(args)  # krotka\n",
    "    print(kwargs)  # słownik\n",
    "\n",
    "d = {'foo': 4, 'bar': 5}\n",
    "say_even_more(*(1, 2, 3), **d)\n",
    "# say_even_more(1, 2, 3, foo=4, bar=5)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "say_even_more((1, 2, 3), {'foo': 4, 'bar': 5})"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "def nwd(a, b):\n",
    "    while b != 0:\n",
    "        a, b = b, a%b\n",
    "    return a\n",
    "    \n",
    "tup = (140, 200)\n",
    "nwd(*tup)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "def nwd(a, b):\n",
    "    while b != 0:\n",
    "        a, b = b, a%b\n",
    "    return a\n",
    "    \n",
    "dictionary = {'a': 140, 'b': 200}\n",
    "nwd(**dictionary)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## CBO - Call by object\n",
    "\n",
    "czyli sposób przekazywania argumentów do funkcji"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def add_something(variable, value):\n",
    "    variable += value\n",
    "    print(\"Inside add_something\", variable)\n",
    "    \n",
    "my_list = [1, 2, 3]\n",
    "\n",
    "print(my_list)\n",
    "add_something(my_list, [4])\n",
    "print(my_list)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "my_int = 3\n",
    "print(my_int)\n",
    "add_something(my_int, 4)\n",
    "print(my_int)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "my_list = [1, 2, 3]\n",
    "\n",
    "def add_something(variable, value):\n",
    "    variable = variable + value\n",
    "    print(\"Inside add_something\", variable)\n",
    "\n",
    "print(my_list)\n",
    "add_something(my_list, [4])\n",
    "print(my_list)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "from copy import copy\n",
    "a_list = [3]\n",
    "b_list = copy(a_list)\n",
    "a_list.extend([1, 2, 3])  \n",
    "print(a_list, id(a_list))\n",
    "print(b_list, id(b_list))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "from copy import deepcopy"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## Funkcje jako zmienne\n",
    "\n",
    "aka. Funkcje obywatelami pierwszej kategorii"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {"slideshow": {
     "slide_type": "subslide"
    }},
   "outputs": [],
   "source": [
    "def add(x, y):\n",
    "    return x + y"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "def apply(f, *args):\n",
    "    return(f(*args))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "apply(add, 2, 2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "l = [\"C\", \"B\", \"a\", \"b\", \"c\", \"A\"]\n",
    "print(sorted(l))\n",
    "print(l)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "sorted(l, key=str.lower)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "say = print\n",
    "say(\"Hello, world!\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "say(say)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def foo():\n",
    "    print(\"Foo\")\n",
    "    \n",
    "print = foo\n",
    "print(\"Hello, world\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "say(\"We are doomed!\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "print = say"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def foo():\n",
    "    return bar()\n",
    "\n",
    "foo()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "def bar():\n",
    "    return 1\n",
    "\n",
    "foo()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## Zmienne \"statyczne\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def func():\n",
    "    if 'time' in dir(func):\n",
    "        func.time += 1\n",
    "    else:\n",
    "        func.time = 1\n",
    "    print(\"func called for the\", func.time, \"time\")"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "for _ in range(3):\n",
    "    func()"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## Zmienne globalne"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {"slideshow": {
     "slide_type": "subslide"
    }},
   "outputs": [],
   "source": [
    "def func():\n",
    "    print(x)\n",
    "    \n",
    "x = 14\n",
    "func()\n",
    "x = 12\n",
    "func()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def func():\n",
    "    x = 4\n",
    "    print(\"Inside:\", x, id(x))\n",
    "    \n",
    "x = 17\n",
    "print(\"Outside:\", x, id(x))\n",
    "func()\n",
    "print(\"Outside:\", x, id(x))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def func():\n",
    "    x = [4]\n",
    "    print(\"Inside:\", x, id(x))\n",
    "    \n",
    "x = [17]\n",
    "print(\"Outside:\", x, id(x))\n",
    "func()\n",
    "print(\"Outside:\", x, id(x))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def func():\n",
    "    print(x)\n",
    "    x = 12\n",
    "    print(x)\n",
    "\n",
    "x = 8\n",
    "func()\n",
    "print(x)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def func2():\n",
    "    global x\n",
    "    print('x is', x)\n",
    "    x = 2\n",
    "    print('Changed global x to', x)\n",
    "    \n",
    "x = 50\n",
    "func2()\n",
    "print(x)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## Funkcje zagnieżdżone"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {"slideshow": {
     "slide_type": "subslide"
    }},
   "outputs": [],
   "source": [
    "def outer():\n",
    "    x = 137\n",
    "    def inner():\n",
    "        print(x)\n",
    "    x = 11\n",
    "    inner()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "outer()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def outer():\n",
    "    y = 137\n",
    "    def inner():\n",
    "        nonlocal y\n",
    "        print(\"inner\", y)\n",
    "        y = 0\n",
    "    print(\"outer pre\", y)\n",
    "    inner()\n",
    "    print(\"outer post\", y)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "outer()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "print = 10\n",
    "print(2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "dir()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "del print\n",
    "print(dir())"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "source": [
    "Rejony poszukiwania symbolu:\n",
    "- symbole lokalne funkcji\n",
    "- symbole lokalne funkcji zewnętrznej\n",
    "- i jeszcze bardziej zewnętrznej\n",
    "- ...\n",
    "- symbole globalne (modułu)\n",
    "- symbole wbudowane"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## Domknięcia (closures)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "source": [
    "#### Domknięcie - funkcja wraz z otoczeniem referencyjnym (wszystkie zmienne z czasu utworzenia) - dostępne nawet po opuszczeniu otoczenia leksykalnego"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {"slideshow": {
     "slide_type": "fragment"
    }},
   "source": [
    "![](img/Lecture/long_words.jpg)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def outer(y):\n",
    "    def inner():\n",
    "        print(y)\n",
    "    return inner"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "inner1 = outer(11)\n",
    "inner2 = outer(111)\n",
    "inner1()\n",
    "inner2()\n",
    "print(id(inner1))\n",
    "print(id(inner2))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def generate_power_func(n):\n",
    "    print(\"id(n): %X\" % id(n))\n",
    "    def nth_power(x):\n",
    "        return x**n\n",
    "    print(\"id(nth_power): %X\" % id(nth_power))\n",
    "    return nth_power"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "raised_to_4 = generate_power_func(4)\n",
    "raised_to_4"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "raised_to_4(2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "sqr = generate_power_func(2)\n",
    "print(sqr(3))\n",
    "print(raised_to_4(3))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "nth_power(3)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "del generate_power_func"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "generate_power_func(1)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "print(raised_to_4(2))\n",
    "raised_to_4"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "raised_to_4.__closure__[0].cell_contents"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "-"
    }
   },
   "outputs": [],
   "source": [
    "sqr.__closure__[0].cell_contents"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {},
   "outputs": [],
   "source": [
    "print(sqr.__closure__)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "def outer():\n",
    "    z = 7\n",
    "    def medium():\n",
    "#         nonlocal z\n",
    "        z = 4\n",
    "        def inner():\n",
    "            nonlocal z\n",
    "            z = 3\n",
    "        inner()\n",
    "    medium()\n",
    "    print(z)\n",
    "\n",
    "outer()"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "from operator import itemgetter\n",
    "l = [(1, 10, 2, 5), (2, 9, 1, 5), (3, 8, 2, 6), (4, 7, 1, 6)]\n",
    "sorted(l, key=itemgetter(1))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "sorted(l, key=itemgetter(2))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "sorted(l, key=itemgetter(3, 2))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "sorted(l, key=itemgetter(2, 3))"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "source": [
    "### Domknięcie w Groovy\n",
    "\n",
    "    def localMethod() {\n",
    "      def localVariable = new java.util.Date()\n",
    "      return { println localVariable }\n",
    "    }\n",
    "    def clos = localMethod()\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "source": [
    "### Domknięcie w JavaScript\n",
    "\n",
    "    function createMarker(point, number) {\n",
    "        var marker = new GMarker(point);\n",
    "        var message = [\"This\",\"is\",\"the\",\"secret\",\"message\"];\n",
    "        marker.value = number;\n",
    "        GEvent.addListener(marker, \"click\", function() {\n",
    "            var myHtml = \"<b>#\" + number + \"</b><br/>\" +\n",
    "                message[number -1];\n",
    "            map.openInfoWindowHtml(point, myHtml);\n",
    "        });\n",
    "        return marker;\n",
    "    }\n",
    "\n"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {"slideshow": {
     "slide_type": "subslide"
    }},
   "source": [
    "## Funkcje w telegraficznym skrócie:\n",
    "- def + lista parametrów + dwukropek + ciało funkcji\n",
    "- nie można ich przeciążać, tylko redefiniować\n",
    "- parametry mogą mieć wartości domyślne (niemodyfikowalne)\n",
    "- modyfikowalne argumenty są modyfikowalne (sic)\n",
    "- można przyjąć dowolnie dużo argumentów pozycyjnych (`*args`) i nazwanych (`**kwargs`)\n",
    "- obywatele pierwszej kategorii - można je przypisywać do zmiennych, przekazywać do funkcji, zwracać z funkcji (jako domknięcie)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "slide"
    }
   },
   "source": [
    "## Wyrażenia lambda"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "source": [
    "* Funkcja nienazwana utworzona w miejscu (anonimowa)\n",
    "* Można ją przypisać do zmiennej (ale się nie powinno)\n",
    "* Najczęściej używamy jej przy programowaniu funkcyjnym (wstrzykujemy logikę kodu do funkcji jako argument, np. patrz sortowanie)\n",
    "* Ciało funkcji lambda składa się z pojedynczego wyrażenia, którego ewaluacja zwracana jest jako wynik\n",
    "* Historia http://python-history.blogspot.com/2009/04/origins-of-pythons-functional-features.html"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "lambda x=1: x + 1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "subslide"
    }
   },
   "outputs": [],
   "source": [
    "operator_dodaj = lambda x, y: x + y\n",
    "operator_dodaj(1, 2)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "lambda x: \"big\" if x > 100 else \"small\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "f = lambda s : \" \".join(s.split())\n",
    "text = '''bla bla\n",
    "bli      blu\n",
    "blurp\n",
    "'''\n",
    "f(text)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "source": [
    "Czy lambda może coś wypisać?"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": null,
   "metadata": {
    "slideshow": {
     "slide_type": "fragment"
    }
   },
   "outputs": [],
   "source": [
    "sqr = lambda x: print(x) or x**2\n",
    "sqr(4)"
   ]
  }
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