{ "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": 1, "metadata": { "slideshow": { "slide_type": "fragment" } }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "0\nPython 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": 6, "metadata": { "slideshow": { "slide_type": "fragment" } }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "\n\n" ] } ], "source": [ "class NajprostszaKlasa:\n", " pass\n", "\n", "nasza_klasa = NajprostszaKlasa() # Uwaga na nawiasy na końcu!\n", "print(type(nasza_klasa))\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": 14, "metadata": { "slideshow": { "slide_type": "fragment" } }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "2\n<__main__.Punkt instance at 0x00000000049B3CC8>\n" ] } ], "source": [ "class Punkt:\n", " def __init__(self, x, y=0):\n", " self.x = x\n", " self.y = y\n", " \n", "# self jak this w C\n", "\n", "punkt = Punkt(2)\n", "print(punkt.x)\n", "print(punkt)" ] }, { "cell_type": "code", "execution_count": 20, "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", " #metoda - jedynym argumentem jest self\n", " #funkcja - \n", " \n", " def dodaj_wierzcholek(self, x):\n", " self.vertexes.append(x)" ] }, { "cell_type": "code", "execution_count": 22, "metadata": { "collapsed": true, "slideshow": { "slide_type": "slide" } }, "outputs": [], "source": [ "#dziedziczenie\n", "\n", "class Prostokat(Figura):\n", " def __init__(self, vertexes):\n", " super().__init__(vertexes)\n", " #lub self.vertexes = vertexes\n", " def czy_jestem_kwadratem(self):\n", " pass\n", " " ] }, { "cell_type": "code", "execution_count": 41, "metadata": { "slideshow": { "slide_type": "slide" } }, "outputs": [ { "data": { "text/plain": [ "3" ] }, "execution_count": 41, "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)]))\n", "o = Figura([Punkt(2,3), Punkt(3,4), Punkt(0, 0)])\n", "len(o)\n", "o.__len__()\n", "o.liczba_wierzcholkow()" ] }, { "cell_type": "markdown", "metadata": { "slideshow": { "slide_type": "slide" } }, "source": [ "## Dobre praktyki: komentarze" ] }, { "cell_type": "code", "execution_count": 33, "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": 34, "metadata": { "slideshow": { "slide_type": "slide" } }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Help on class Punkt in module __main__:\n\nclass Punkt(__builtin__.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\u001b[0m in \u001b[0;36m\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": 42, "metadata": { "slideshow": { "slide_type": "fragment" } }, "outputs": [ { "ename": "TypeError", "evalue": "instance has no next() method", "traceback": [ "\u001b[1;31m\u001b[0m", "\u001b[1;31mTypeError\u001b[0mTraceback (most recent call last)", "\u001b[1;32m\u001b[0m in \u001b[0;36m\u001b[1;34m()\u001b[0m\n\u001b[0;32m 13\u001b[0m \u001b[1;32mreturn\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mvertexes\u001b[0m\u001b[1;33m[\u001b[0m\u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mindex\u001b[0m\u001b[1;33m]\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m 14\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m---> 15\u001b[1;33m \u001b[1;32mfor\u001b[0m \u001b[0mv\u001b[0m \u001b[1;32min\u001b[0m \u001b[0mFigura\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;33m[\u001b[0m\u001b[0mPunkt\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m2\u001b[0m\u001b[1;33m,\u001b[0m\u001b[1;36m3\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mPunkt\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m3\u001b[0m\u001b[1;33m,\u001b[0m\u001b[1;36m4\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mPunkt\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;36m0\u001b[0m\u001b[1;33m,\u001b[0m \u001b[1;36m0\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m]\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m 16\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mv\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n", "\u001b[1;31mTypeError\u001b[0m: instance has no next() method" ], "output_type": "error" } ], "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": 1, "metadata": { "slideshow": { "slide_type": "fragment" } }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "79384200\n48959560\n0\n0\n" ] } ], "source": [ "class Klasa:\n", " atrybut = 0\n", "\n", "klasa = Klasa()\n", "#klasa2 = Klasa\n", "#klasa2.atrybut=1\n", "print(id(Klasa))\n", "klasa2 = Klasa()\n", "print(id(klasa2))\n", "klasa2.atrybut=1\n", "\n", "print(Klasa.atrybut) \n", "#atrybut wspólny dla wszystkich instancji\n", "print(klasa.atrybut)\n", "\n", "klasa.temp = []" ] }, { "cell_type": "code", "execution_count": 62, "metadata": { "slideshow": { "slide_type": "slide" } }, "outputs": [ { "ename": "TypeError", "evalue": "unbound method metoda() must be called with Klasa instance as first argument (got nothing instead)", "traceback": [ "\u001b[1;31m\u001b[0m", "\u001b[1;31mTypeError\u001b[0mTraceback (most recent call last)", "\u001b[1;32m\u001b[0m in \u001b[0;36m\u001b[1;34m()\u001b[0m\n\u001b[0;32m 6\u001b[0m \u001b[1;32mprint\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"Jestem statyczna!\"\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m 7\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 8\u001b[1;33m \u001b[0mKlasa\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mmetoda\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m", "\u001b[1;31mTypeError\u001b[0m: unbound method metoda() must be called with Klasa instance as first argument (got nothing instead)" ], "output_type": "error" } ], "source": [ "class Klasa:\n", " def __init__(self):\n", " self.t = 0\n", " def metoda():\n", " # nie będzie działać self.t = 0\n", " print(\"Jestem statyczna!\")\n", "\n", "Klasa.metoda()" ] }, { "cell_type": "markdown", "metadata": { "slideshow": { "slide_type": "slide" } }, "source": [ "## Wyjątki" ] }, { "cell_type": "code", "execution_count": 1, "metadata": { "slideshow": { "slide_type": "fragment" } }, "outputs": [ { "ename": "IOError", "evalue": "[Errno 2] No such file or directory: 'nieistniej\\xc4\\x85cy_plik.txt'", "traceback": [ "\u001b[1;31m\u001b[0m", "\u001b[1;31mIOError\u001b[0mTraceback (most recent call last)", "\u001b[1;32m\u001b[0m in \u001b[0;36m\u001b[1;34m()\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[1;32mwith\u001b[0m \u001b[0mopen\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"nieistniejący_plik.txt\"\u001b[0m\u001b[1;33m)\u001b[0m \u001b[1;32mas\u001b[0m \u001b[0mplik\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m 2\u001b[0m \u001b[0mcontent\u001b[0m \u001b[1;33m=\u001b[0m \u001b[0mplik\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mread\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n", "\u001b[1;31mIOError\u001b[0m: [Errno 2] No such file or directory: 'nieistniej\\xc4\\x85cy_plik.txt'" ], "output_type": "error" } ], "source": [ "with open(\"nieistniejący_plik.txt\") as plik:\n", " content = plik.read()" ] }, { "cell_type": "code", "execution_count": 31, "metadata": { "slideshow": { "slide_type": "slide" } }, "outputs": [], "source": [ "from pandas.compat import FileNotFoundError\n", "\n", "try:\n", " with open(\"nieistniejący_plik.txt\") as plik:\n", " content = plik.read()\n", "except FileNotFoundError:\n", " contenct = \"\"" ] }, { "cell_type": "code", "execution_count": 32, "metadata": { "slideshow": { "slide_type": "slide" } }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Warning [Errno 2] No such file or directory: 'nieistniej\\xc4\\x85cy_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": 13, "metadata": { "slideshow": { "slide_type": "slide" } }, "outputs": [ { "name": "stdout", "output_type": "stream", "text": [ "Warning [Errno 2] No such file or directory: 'nieistniej\\xc4\\x85cy_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": 14, "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": 19, "metadata": { "collapsed": true, "slideshow": { "slide_type": "slide" } }, "outputs": [ { "ename": "Exception", "evalue": "Empty list of vertexes", "traceback": [ "\u001b[1;31m\u001b[0m", "\u001b[1;31mException\u001b[0mTraceback (most recent call last)", "\u001b[1;32m\u001b[0m in \u001b[0;36m\u001b[1;34m()\u001b[0m\n\u001b[0;32m 5\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mvertexes\u001b[0m \u001b[1;33m=\u001b[0m \u001b[0mvertexes\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m 6\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 7\u001b[1;33m \u001b[0mfigura\u001b[0m \u001b[1;33m=\u001b[0m \u001b[0mFigura\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;33m[\u001b[0m\u001b[1;33m]\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m", "\u001b[1;32m\u001b[0m in \u001b[0;36m__init__\u001b[1;34m(self, vertexes)\u001b[0m\n\u001b[0;32m 2\u001b[0m \u001b[1;32mdef\u001b[0m \u001b[0m__init__\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mself\u001b[0m\u001b[1;33m,\u001b[0m \u001b[0mvertexes\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m 3\u001b[0m \u001b[1;32mif\u001b[0m \u001b[0mlen\u001b[0m\u001b[1;33m(\u001b[0m\u001b[0mvertexes\u001b[0m\u001b[1;33m)\u001b[0m \u001b[1;33m==\u001b[0m \u001b[1;36m0\u001b[0m\u001b[1;33m:\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[1;32m----> 4\u001b[1;33m \u001b[1;32mraise\u001b[0m \u001b[0mException\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"Empty list of vertexes\"\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m\u001b[0;32m 5\u001b[0m \u001b[0mself\u001b[0m\u001b[1;33m.\u001b[0m\u001b[0mvertexes\u001b[0m \u001b[1;33m=\u001b[0m \u001b[0mvertexes\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0;32m 6\u001b[0m \u001b[1;33m\u001b[0m\u001b[0m\n", "\u001b[1;31mException\u001b[0m: Empty list of vertexes" ], "output_type": "error" } ], "source": [ "class Figura:\n", " def __init__(self, vertexes):\n", " if len(vertexes) == 0:\n", " raise Exception(\"Empty list of vertexes\")\n", " self.vertexes = vertexes\n", " \n", "figura = Figura([])" ] }, { "cell_type": "code", "execution_count": 27, "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": 34, "metadata": { "slideshow": { "slide_type": "fragment" } }, "outputs": [ { "ename": "MyError", "evalue": "Coś poszło nie tak!", "traceback": [ "\u001b[1;31m\u001b[0m", "\u001b[1;31mMyError\u001b[0mTraceback (most recent call last)", "\u001b[1;32m\u001b[0m in \u001b[0;36m\u001b[1;34m()\u001b[0m\n\u001b[1;32m----> 1\u001b[1;33m \u001b[1;32mraise\u001b[0m \u001b[0mMyError\u001b[0m\u001b[1;33m(\u001b[0m\u001b[1;34m\"Coś poszło nie tak!\"\u001b[0m\u001b[1;33m)\u001b[0m\u001b[1;33m\u001b[0m\u001b[0m\n\u001b[0m", "\u001b[1;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 }