1 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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2 % Tutorial slides on Python. |
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3 % |
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4 % Author: Prabhu Ramachandran <prabhu at aero.iitb.ac.in> |
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5 % Copyright (c) 2005-2008, Prabhu Ramachandran |
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6 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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7 |
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8 \documentclass[14pt,compress]{beamer} |
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9 %\documentclass[draft]{beamer} |
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10 %\documentclass[compress,handout]{beamer} |
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11 %\usepackage{pgfpages} |
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12 %\pgfpagesuselayout{2 on 1}[a4paper,border shrink=5mm] |
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13 |
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14 % Modified from: generic-ornate-15min-45min.de.tex |
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15 \mode<presentation> |
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16 { |
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17 \usetheme{Warsaw} |
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18 \useoutertheme{split} |
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19 \setbeamercovered{transparent} |
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20 } |
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21 |
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22 \usepackage[english]{babel} |
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23 \usepackage[latin1]{inputenc} |
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24 %\usepackage{times} |
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25 \usepackage[T1]{fontenc} |
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26 |
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27 % Taken from Fernando's slides. |
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28 \usepackage{ae,aecompl} |
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29 \usepackage{mathpazo,courier,euler} |
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30 \usepackage[scaled=.95]{helvet} |
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31 |
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32 \definecolor{darkgreen}{rgb}{0,0.5,0} |
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33 |
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34 \usepackage{listings} |
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35 \lstset{language=Python, |
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36 basicstyle=\ttfamily, |
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37 commentstyle=\color{red}\itshape, |
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38 stringstyle=\color{darkgreen}, |
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39 showstringspaces=false, |
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40 keywordstyle=\color{blue}\bfseries} |
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41 |
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42 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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43 % Macros |
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44 \setbeamercolor{emphbar}{bg=blue!20, fg=black} |
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45 \newcommand{\emphbar}[1] |
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46 {\begin{beamercolorbox}[rounded=true]{emphbar} |
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47 {#1} |
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48 \end{beamercolorbox} |
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49 } |
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50 \newcounter{time} |
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51 \setcounter{time}{0} |
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52 \newcommand{\inctime}[1]{\addtocounter{time}{#1}{\tiny \thetime\ m}} |
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53 |
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54 \newcommand{\typ}[1]{\texttt{#1}} |
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55 |
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56 \newcommand{\kwrd}[1]{ \texttt{\textbf{\color{blue}{#1}}} } |
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57 |
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58 %%% This is from Fernando's setup. |
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59 % \usepackage{color} |
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60 % \definecolor{orange}{cmyk}{0,0.4,0.8,0.2} |
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61 % % Use and configure listings package for nicely formatted code |
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62 % \usepackage{listings} |
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63 % \lstset{ |
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64 % language=Python, |
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65 % basicstyle=\small\ttfamily, |
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66 % commentstyle=\ttfamily\color{blue}, |
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67 % stringstyle=\ttfamily\color{orange}, |
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68 % showstringspaces=false, |
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69 % breaklines=true, |
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70 % postbreak = \space\dots |
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71 % } |
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72 |
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73 |
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74 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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75 % Title page |
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76 \title[Basic Python]{Python:\\Modular Code, Handling Files and Objects} |
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77 |
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78 \author[FOSSEE Team] {Asokan Pichai\\Prabhu Ramachandran} |
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79 |
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80 \institute[IIT Bombay] {Department of Aerospace Engineering\\IIT Bombay} |
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81 \date[] {10, October 2009} |
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82 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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83 |
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84 %\pgfdeclareimage[height=0.75cm]{iitmlogo}{iitmlogo} |
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85 %\logo{\pgfuseimage{iitmlogo}} |
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86 |
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87 |
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88 %% Delete this, if you do not want the table of contents to pop up at |
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89 %% the beginning of each subsection: |
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90 \AtBeginSubsection[] |
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91 { |
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92 \begin{frame}<beamer> |
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93 \frametitle{Outline} |
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94 \tableofcontents[currentsection,currentsubsection] |
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95 \end{frame} |
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96 } |
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97 |
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98 |
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99 % If you wish to uncover everything in a step-wise fashion, uncomment |
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100 % the following command: |
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101 %\beamerdefaultoverlayspecification{<+->} |
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102 |
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103 %\includeonlyframes{current,current1,current2,current3,current4,current5,current6} |
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104 |
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105 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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106 % DOCUMENT STARTS |
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107 \begin{document} |
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108 |
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109 \begin{frame} |
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110 \titlepage |
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111 \end{frame} |
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112 |
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113 \section{Python} |
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114 |
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115 \begin{frame} |
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116 {Problem set 3} |
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117 As you can guess, idea is to use \kwrd{for}! |
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118 \end{frame} |
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119 |
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120 \begin{frame}{Problem 3.1} |
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121 Which of the earlier problems is simpler when we use \kwrd{for} instead of \kwrd{while}? |
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122 \end{frame} |
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123 |
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124 \begin{frame}{Problem 3.2} |
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125 Given an empty chessboard and one Bishop placed in any square, say (r, c), generate the list of all squares the Bishop could move to. |
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126 \end{frame} |
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127 |
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128 \begin{frame}[fragile] |
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129 \frametitle{Problem 3.3} |
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130 |
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131 Given two real numbers \typ{a, b}, and an integer \typ{N}, write a |
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132 function named \typ{linspace( a, b, N)} that returns an ordered list |
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133 of \typ{N} points starting with \typ{a} and ending in \typ{b} and |
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134 equally spaced.\\ |
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135 |
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136 For example, \typ{linspace(0, 5, 11)}, should return, \\ |
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137 \begin{lstlisting} |
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138 [ 0.0 , 0.5, 1.0 , 1.5, 2.0 , 2.5, |
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139 3.0 , 3.5, 4.0 , 4.5, 5.0 ] |
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140 \end{lstlisting} |
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141 \end{frame} |
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142 |
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143 \begin{frame}[fragile] |
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144 \frametitle{Problem 3.4a (optional)} |
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145 |
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146 Use the \typ{linspace} function and generate a list of N tuples of the form\\ |
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147 \typ{[($x_1$,f($x_1$)),($x_2$,f($x_2$)),\ldots,($x_N$,f($x_N$))]}\\for the following functions,\begin{itemize} |
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148 \item \typ{f(x) = sin(x)} |
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149 \item \typ{f(x) = sin(x) + sin(10*x)}. |
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150 \end{itemize} |
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151 \end{frame} |
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152 |
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153 \begin{frame}[fragile] |
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154 \frametitle{Problem 3.4b (optional)} |
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155 |
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156 Using the tuples generated earlier, determine the intervals where the roots of the functions lie. |
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157 |
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158 \inctime{15} |
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159 \end{frame} |
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160 |
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161 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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162 % TIME: 15 m, running 185m |
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163 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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164 |
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165 \subsection{IO} |
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166 |
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167 \begin{frame}[fragile] |
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168 \frametitle{Simple tokenizing and parsing} |
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169 \begin{lstlisting} |
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170 s = """The quick brown fox jumped |
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171 over the lazy dog""" |
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172 for word in s.split(): |
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173 print word.capitalize() |
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174 \end{lstlisting} |
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175 \end{frame} |
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176 |
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177 \begin{frame}[fragile] |
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178 \frametitle{Problem 4.1} |
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179 Given a string like, ``1, 3-7, 12, 15, 18-21'', produce the list \\ |
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180 \begin{lstlisting} |
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181 [1,3,4,5,6,7,12,15,18,19,20,21] |
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182 \end{lstlisting} |
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183 \end{frame} |
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184 |
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185 \begin{frame}[fragile] |
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186 \frametitle{File handling} |
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187 \begin{lstlisting} |
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188 >>> f = open('/path/to/file_name') |
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189 >>> data = f.read() # Read entire file. |
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190 >>> line = f.readline() # Read one line. |
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191 >>> f.close() # close the file. |
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192 \end{lstlisting} |
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193 Writing files |
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194 \begin{lstlisting} |
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195 >>> f = open('/path/to/file_name', 'w') |
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196 >>> f.write('hello world\n') |
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197 >>> f.close() |
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198 \end{lstlisting} |
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199 \begin{itemize} |
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200 \item Everything read or written is a string |
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201 \end{itemize} |
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202 \emphbar{Try \typ{file?} for more help} |
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203 \end{frame} |
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204 |
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205 \begin{frame}[fragile] |
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206 \frametitle{File and \kwrd{for}} |
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207 \begin{lstlisting} |
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208 >>> f = open('/path/to/file_name') |
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209 >>> for line in f: |
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210 ... print line |
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211 ... |
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212 \end{lstlisting} |
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213 \end{frame} |
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214 |
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215 \begin{frame}{Problem 4.2} |
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216 The given file has lakhs of records in the form:\\ |
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217 \typ{RGN;ID;NAME;MARK1;\ldots;MARK5;TOTAL;PFW}\\ |
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218 Some entries may be empty. Read the data from this file and print the |
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219 name of the student with the maximum total marks. |
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220 \end{frame} |
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221 |
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222 \begin{frame}{Problem 4.3} |
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223 For the same data file compute the average marks in different |
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224 subjects, the student with the maximum mark in each subject and also |
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225 the standard deviation of the marks. Do this efficiently. |
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226 |
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227 \inctime{20} |
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228 \end{frame} |
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229 |
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230 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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231 % TIME: 20 m, running 205m |
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232 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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233 |
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234 \subsection{Modules} |
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235 |
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236 \begin{frame}[fragile] |
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237 {Modules} |
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238 \begin{lstlisting} |
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239 >>> sqrt(2) |
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240 Traceback (most recent call last): |
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241 File "<stdin>", line 1, in <module> |
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242 NameError: name 'sqrt' is not defined |
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243 >>> import math |
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244 >>> math.sqrt(2) |
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245 1.4142135623730951 |
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246 \end{lstlisting} |
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247 \end{frame} |
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248 |
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249 \begin{frame}[fragile] |
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250 {Modules} |
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251 \begin{itemize} |
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252 \item The \kwrd{import} keyword ``loads'' a module |
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253 \item One can also use: |
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254 \begin{lstlisting} |
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255 >>> from math import sqrt |
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256 >>> from math import * |
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257 \end{lstlisting} |
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258 \item What is the difference? |
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259 \item \alert{Use the later only in interactive mode} |
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260 \end{itemize} |
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261 \emphbar{Package hierarchies} |
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262 \begin{lstlisting} |
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263 >>> from os.path import exists |
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264 \end{lstlisting} |
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265 \end{frame} |
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266 |
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267 \begin{frame} |
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268 \frametitle{Modules: Standard library} |
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269 \begin{itemize} |
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270 \item Very powerful, ``Batteries included'' |
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271 \item Some standard modules: |
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272 \begin{itemize} |
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273 \item Math: \typ{math}, \typ{random} |
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274 \item Internet access: \typ{urllib2}, \typ{smtplib} |
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275 \item System, Command line arguments: \typ{sys} |
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276 \item Operating system interface: \typ{os} |
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277 \item Regular expressions: \typ{re} |
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278 \item Compression: \typ{gzip}, \typ{zipfile}, and \typ{tarfile} |
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279 \item And a whole lot more! |
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280 \end{itemize} |
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281 \item Check out the Python Library reference: |
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282 \url{http://docs.python.org/library/} |
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283 \end{itemize} |
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284 \end{frame} |
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285 |
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286 \begin{frame}[fragile] |
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287 {Modules of special interest} |
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288 \begin{description}[matplotlibfor2d] |
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289 |
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290 \item[\typ{numpy}] Efficient, powerful numeric arrays |
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291 |
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292 \item[\typ{matplotlib}] Easy, interactive, 2D plotting |
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293 |
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294 \item[\typ{scipy}] statistics, optimization, integration, linear |
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295 algebra, Fourier transforms, signal and image processing, |
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296 genetic algorithms, ODE solvers, special functions, and more |
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297 |
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298 \item[Mayavi] Easy, interactive, 3D plotting |
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299 |
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300 \end{description} |
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301 \end{frame} |
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302 |
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303 \begin{frame}[fragile] |
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304 {Creating your own modules} |
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305 \begin{itemize} |
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306 \item Define variables, functions and classes in a file with a |
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307 \typ{.py} extension |
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308 \item This file becomes a module! |
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309 \item Accessible when in the current directory |
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310 \item Use \typ{cd} in IPython to change directory |
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311 |
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312 \item Naming your module |
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313 \end{itemize} |
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314 \end{frame} |
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315 |
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316 \begin{frame}[fragile] |
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317 \frametitle{Modules: example} |
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318 \begin{lstlisting} |
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319 # --- arith.py --- |
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320 def gcd(a, b): |
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321 if a%b == 0: return b |
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322 return gcd(b, a%b) |
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323 def lcm(a, b): |
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324 return a*b/gcd(a, b) |
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325 # ------------------ |
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326 >>> import arith |
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327 >>> arith.gcd(26, 65) |
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328 13 |
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329 >>> arith.lcm(26, 65) |
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330 130 |
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331 \end{lstlisting} |
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332 \end{frame} |
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333 |
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334 \begin{frame}[fragile] |
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335 \frametitle{Problem 5.1} |
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336 |
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337 Put all the functions you have written so far as part of the problems |
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338 into one module called \typ{iitb.py} and use this module from IPython. |
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339 |
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340 \inctime{20} |
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341 \end{frame} |
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342 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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343 % TIME: 20 m, running 225m |
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344 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% |
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345 |
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346 \subsection{Objects} |
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347 \begin{frame}{Objects in Python} |
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348 \begin{itemize} |
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349 \item What is an Object? (Types and classes) |
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350 \item identity |
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351 \item type |
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352 \item method |
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353 \end{itemize} |
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354 \end{frame} |
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355 |
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356 \begin{frame}[fragile] |
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357 \frametitle{Why are they useful?} |
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358 \small |
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359 \begin{lstlisting} |
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360 for element in (1, 2, 3): |
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361 print element |
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362 for key in {'one':1, 'two':2}: |
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363 print key |
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364 for char in "123": |
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365 print char |
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366 for line in open("myfile.txt"): |
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367 print line |
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368 for line in urllib2.urlopen('http://site.com'): |
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369 print line |
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370 \end{lstlisting} |
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371 \end{frame} |
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372 |
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373 \begin{frame}{And the winner is \ldots OBJECTS!} |
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374 All objects providing a similar inteface can be used the same way.\\ |
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375 Functions (and others) are first-class objects. Can be passed to and returned from functions. |
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376 \inctime{10} |
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377 \end{frame} |
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378 |
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379 \subsection{Coding Style in Python} |
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380 \begin{frame}{Readability and Consistency} |
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381 \begin{itemize} |
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382 \item Readability Counts!-Code is read more often than its written. |
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383 \item Consistency! |
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384 \item Know when to be inconsistent. |
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385 \end{itemize} |
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386 \end{frame} |
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387 |
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388 \begin{frame}[fragile] |
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389 \frametitle{Code Layout} |
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390 \begin{itemize} |
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391 \item Indentation |
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392 \item Tabs or Spaces?? |
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393 \item Maximum Line Length |
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394 \item Blank Lines |
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395 \item Encodings |
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396 \end{itemize} |
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397 \end{frame} |
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398 |
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399 \begin{frame}{Whitespaces in Expressions} |
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400 \begin{itemize} |
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401 \item When to use extraneous whitespaces?? |
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402 \item When to avoid extra whitespaces?? |
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403 \item Use one statement per line |
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404 \end{itemize} |
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405 \end{frame} |
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406 |
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407 \begin{frame}{Comments} |
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408 \begin{itemize} |
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409 \item No comments better than contradicting comments |
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410 \item Block comments |
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411 \item Inline comments |
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412 \end{itemize} |
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413 \end{frame} |
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414 |
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415 \begin{frame}{Docstrings} |
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416 \begin{itemize} |
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417 \item When to write docstrings? |
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418 \item Ending the docstrings |
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419 \item One liner docstrings |
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420 \end{itemize} |
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421 \end{frame} |
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422 \inctime{10} |
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423 \end{document} |
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