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{
"cells": [
{
"cell_type": "markdown",
"metadata": {
"collapsed": true,
"slideshow": {
"slide_type": "slide"
}
},
"source": [
"# Wprowadzenie do Pythona: Klasy\n",
"\n",
"## Tomasz Dwojak\n",
"\n",
"### 3 grudnia 2017"
]
},
{
"cell_type": "markdown",
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"source": [
"# Plan na dziś:\n",
" * klasy,\n",
" * wyjątki."
]
},
{
"cell_type": "markdown",
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"source": [
"## Python jest językiem obiektowym \n",
" * Wszystko jest obiektem: liczby, napisy, None, funkcje, moduły (biblioteki)..."
]
},
{
"cell_type": "code",
"execution_count": 11,
"metadata": {
"slideshow": {
"slide_type": "fragment"
}
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"0\n",
"Python da się lubić !\n"
]
}
],
"source": [
"print((2017).imag)\n",
"print(' '.join(['Python', 'da', 'się', 'lubić', '!']))"
]
},
{
"cell_type": "markdown",
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"source": [
"## Konstrukcja"
]
},
{
"cell_type": "code",
"execution_count": 18,
"metadata": {
"slideshow": {
"slide_type": "fragment"
}
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"<class '__main__.NajprostszaKlasa'>\n"
]
}
],
"source": [
"class NajprostszaKlasa:\n",
" pass\n",
"\n",
"nasza_klasa = NajprostszaKlasa() # Uwaga na nawiasy na końcu!\n",
"print(type(nasza_klasa))"
]
},
{
"cell_type": "markdown",
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"source": [
"## (Pseudo) Konstruktor \n",
"\n"
]
},
{
"cell_type": "code",
"execution_count": 30,
"metadata": {
"slideshow": {
"slide_type": "fragment"
}
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"2\n"
]
}
],
"source": [
"class Punkt:\n",
" def __init__(self, x, y):\n",
" self.x = x\n",
" self.y = y\n",
"\n",
"punkt = Punkt(2, 3)\n",
"print(punkt.x)"
]
},
{
"cell_type": "code",
"execution_count": 25,
"metadata": {
"collapsed": true,
"slideshow": {
"slide_type": "slide"
}
},
"outputs": [],
"source": [
"class Figura:\n",
" def __init__(self, vertexes):\n",
" self.vertexes = vertexes\n",
" \n",
" def liczba_wierzcholkow(self):\n",
" return len(self.vertexes)\n",
" \n",
" def dodaj_wierzcholek(self, x):\n",
" self.vertexes.append(x)"
]
},
{
"cell_type": "code",
"execution_count": 26,
"metadata": {
"collapsed": true,
"slideshow": {
"slide_type": "slide"
}
},
"outputs": [],
"source": [
"class Prostokat(Figura):\n",
" def __init__(self, vertexes):\n",
" super().__init__(vertexes)\n",
" \n",
" def czy_jestem_kwadratem(self):\n",
" pass\n",
" "
]
},
{
"cell_type": "code",
"execution_count": 28,
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"outputs": [
{
"data": {
"text/plain": [
"3"
]
},
"execution_count": 28,
"metadata": {},
"output_type": "execute_result"
}
],
"source": [
"class Figura:\n",
" def __init__(self, vertexes):\n",
" self.vertexes = vertexes\n",
" \n",
" def liczba_wierzcholkow(self):\n",
" return len(self.vertexes)\n",
" \n",
" def __len__(self):\n",
" return self.liczba_wierzcholkow()\n",
" \n",
"len(Figura([Punkt(2,3), Punkt(3,4), Punkt(0, 0)]))"
]
},
{
"cell_type": "markdown",
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"source": [
"## Dobre praktyki: komentarze"
]
},
{
"cell_type": "code",
"execution_count": 4,
"metadata": {
"slideshow": {
"slide_type": "fragment"
}
},
"outputs": [],
"source": [
"class Punkt(object):\n",
" \"\"\"Klasa reprezentująca punkt w 2D.\"\"\"\n",
" def __init__(self, x, y):\n",
" \"\"\"opis argumentów x i y.\"\"\"\n",
" self.x = x\n",
" self.y = y"
]
},
{
"cell_type": "code",
"execution_count": 5,
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Help on class Punkt in module __main__:\n",
"\n",
"class Punkt(builtins.object)\n",
" | Klasa reprezentująca punkt w 2D.\n",
" | \n",
" | Methods defined here:\n",
" | \n",
" | __init__(self, x, y)\n",
" | opis argumentów x i y.\n",
" | \n",
" | ----------------------------------------------------------------------\n",
" | Data descriptors defined here:\n",
" | \n",
" | __dict__\n",
" | dictionary for instance variables (if defined)\n",
" | \n",
" | __weakref__\n",
" | list of weak references to the object (if defined)\n",
"\n"
]
}
],
"source": [
"help(Punkt)"
]
},
{
"cell_type": "markdown",
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"source": [
"## Enkapsulacja: publiczne czy prywatne?\n",
" * Prywatne zaczynają się od dwóch podkreśleń: ``__``, np. ``def __policz(self)``\n",
" * chronione tylko w konwencji, zaczynają się od '\\_', np. ``def _parse(self)``\n",
" * publiczne jest wszystko co nie zaczyna się od '\\_'."
]
},
{
"cell_type": "code",
"execution_count": 6,
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"outputs": [
{
"ename": "AttributeError",
"evalue": "'Parser' object has no attribute '__parse'",
"traceback": [
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
"\u001b[0;31mAttributeError\u001b[0m Traceback (most recent call last)",
"\u001b[0;32m<ipython-input-6-80ee186598d3>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[1;32m 4\u001b[0m \u001b[0mparser\u001b[0m \u001b[0;34m=\u001b[0m \u001b[0mParser\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[1;32m 5\u001b[0m \u001b[0mparser\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0m_get\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0;32m----> 6\u001b[0;31m \u001b[0mparser\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0m__parse\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
"\u001b[0;31mAttributeError\u001b[0m: 'Parser' object has no attribute '__parse'"
],
"output_type": "error"
}
],
"source": [
"class Parser(object):\n",
" def __parse(self): pass\n",
" def _get(self): pass\n",
"parser = Parser()\n",
"parser._get()\n",
"parser.__parse()"
]
},
{
"cell_type": "markdown",
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"source": [
"## Iteratory"
]
},
{
"cell_type": "code",
"execution_count": 7,
"metadata": {
"slideshow": {
"slide_type": "fragment"
}
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"<__main__.Punkt object at 0x7f728015b358>\n",
"<__main__.Punkt object at 0x7f728015b4a8>\n",
"<__main__.Punkt object at 0x7f728015b438>\n"
]
}
],
"source": [
"class Figura:\n",
" def __init__(self, vertexes):\n",
" self.vertexes = vertexes \n",
" \n",
" def __iter__(self):\n",
" self.index = -1\n",
" return self\n",
" \n",
" def __next__(self):\n",
" self.index += 1\n",
" if self.index == len(self.vertexes):\n",
" raise StopIteration\n",
" return self.vertexes[self.index]\n",
" \n",
"for v in Figura([Punkt(2,3), Punkt(3,4), Punkt(0, 0)]):\n",
" print(v)"
]
},
{
"cell_type": "markdown",
"metadata": {
"collapsed": true,
"slideshow": {
"slide_type": "slide"
}
},
"source": [
"## Atrybuty i metody statyczne"
]
},
{
"cell_type": "code",
"execution_count": 16,
"metadata": {
"slideshow": {
"slide_type": "fragment"
}
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"0\n",
"0\n"
]
}
],
"source": [
"class Klasa:\n",
" atrybut = 0\n",
"\n",
"klasa = Klasa()\n",
"print(Klasa.atrybut)\n",
"print(klasa.atrybut)"
]
},
{
"cell_type": "code",
"execution_count": 19,
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Jestem statyczna!\n"
]
}
],
"source": [
"class Klasa:\n",
" def __init__(self):\n",
" self.t = 0\n",
" def metoda():\n",
" print(\"Jestem statyczna!\")\n",
"\n",
"Klasa.metoda()"
]
},
{
"cell_type": "markdown",
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"source": [
"## Wyjątki"
]
},
{
"cell_type": "code",
"execution_count": 20,
"metadata": {
"slideshow": {
"slide_type": "fragment"
}
},
"outputs": [
{
"ename": "FileNotFoundError",
"evalue": "[Errno 2] No such file or directory: 'nieistniejący_plik.txt'",
"traceback": [
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
"\u001b[0;31mFileNotFoundError\u001b[0m Traceback (most recent call last)",
"\u001b[0;32m<ipython-input-20-41928d542bef>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0;32mwith\u001b[0m \u001b[0mopen\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m\"nieistniejący_plik.txt\"\u001b[0m\u001b[0;34m)\u001b[0m \u001b[0;32mas\u001b[0m \u001b[0mplik\u001b[0m\u001b[0;34m:\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m\u001b[1;32m 2\u001b[0m \u001b[0mprint\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0mplik\u001b[0m\u001b[0;34m.\u001b[0m\u001b[0mread\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n",
"\u001b[0;31mFileNotFoundError\u001b[0m: [Errno 2] No such file or directory: 'nieistniejący_plik.txt'"
],
"output_type": "error"
}
],
"source": [
"with open(\"nieistniejący_plik.txt\") as plik:\n",
" content = plik.read()"
]
},
{
"cell_type": "code",
"execution_count": 23,
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"outputs": [],
"source": [
"try:\n",
" with open(\"nieistniejący_plik.txt\") as plik:\n",
" content = plik.read()\n",
"except FileNotFoundError:\n",
" contenct = \"\""
]
},
{
"cell_type": "code",
"execution_count": 27,
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Warning [Errno 2] No such file or directory: 'nieistniejący_plik.txt'\n"
]
}
],
"source": [
"try:\n",
" with open(\"nieistniejący_plik.txt\") as plik:\n",
" content = plik.read()\n",
"except FileNotFoundError as e:\n",
" print(\"Warning {}\".format(e))\n",
" contenct = \"\""
]
},
{
"cell_type": "code",
"execution_count": 28,
"metadata": {
"slideshow": {
"slide_type": "slide"
}
},
"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"Warning [Errno 2] No such file or directory: 'nieistniejący_plik.txt'\n"
]
}
],
"source": [
"try:\n",
" with open(\"nieistniejący_plik.txt\") as plik:\n",
" content = plik.read()\n",
"except Exception as e:\n",
" print(\"Warning {}\".format(e))\n",
" contenct = \"\""
]
},
{
"cell_type": "code",
"execution_count": 29,
"metadata": {
"collapsed": true,
"slideshow": {
"slide_type": "slide"
}
},
"outputs": [],
"source": [
"try:\n",
" with open(\"nieistniejący_plik.txt\") as plik:\n",
" content = plik.read()\n",
"except:\n",
" contenct = \"\""
]
},
{
"cell_type": "code",
"execution_count": 30,
"metadata": {
"collapsed": true,
"slideshow": {
"slide_type": "slide"
}
},
"outputs": [],
"source": [
"class Figura:\n",
" def __init__(self, vertexes):\n",
" if len(vertexes) == 0:\n",
" raise Exception(\"Empty list of vertexes\")\n",
" self.vertexes = vertexes"
]
},
{
"cell_type": "code",
"execution_count": 35,
"metadata": {
"collapsed": true,
"slideshow": {
"slide_type": "slide"
}
},
"outputs": [],
"source": [
"class MyError(Exception):\n",
" def __init__(self, text):\n",
" self.text = text\n",
" def __str__(self):\n",
" return self.text"
]
},
{
"cell_type": "code",
"execution_count": 36,
"metadata": {
"slideshow": {
"slide_type": "fragment"
}
},
"outputs": [
{
"ename": "MyError",
"evalue": "Coś poszło nie tak!",
"traceback": [
"\u001b[0;31m---------------------------------------------------------------------------\u001b[0m",
"\u001b[0;31mMyError\u001b[0m Traceback (most recent call last)",
"\u001b[0;32m<ipython-input-36-4fb306b42ebc>\u001b[0m in \u001b[0;36m<module>\u001b[0;34m()\u001b[0m\n\u001b[0;32m----> 1\u001b[0;31m \u001b[0;32mraise\u001b[0m \u001b[0mMyError\u001b[0m\u001b[0;34m(\u001b[0m\u001b[0;34m\"Coś poszło nie tak!\"\u001b[0m\u001b[0;34m)\u001b[0m\u001b[0;34m\u001b[0m\u001b[0m\n\u001b[0m",
"\u001b[0;31mMyError\u001b[0m: Coś poszło nie tak!"
],
"output_type": "error"
}
],
"source": [
"raise MyError(\"Coś poszło nie tak!\")"
]
},
{
"cell_type": "code",
"execution_count": null,
"metadata": {
"collapsed": true
},
"outputs": [],
"source": []
}
],
"metadata": {
"celltoolbar": "Slideshow",
"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": "3.6.3"
}
},
"nbformat": 4,
"nbformat_minor": 2
}
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