1 % Created 2010-11-03 Wed 15:37

     2 \documentclass[presentation]{beamer}

     3 \usetheme{Antibes}\usecolortheme{lily}\useoutertheme{infolines}\setbeamercovered{transparent}

     4 \usepackage[latin1]{inputenc}

     5 \usepackage[T1]{fontenc}

     6 \usepackage{graphicx}

     7 \usepackage{longtable}

     8 \usepackage{float}

     9 \usepackage{wrapfig}

    10 \usepackage{soul}

    11 \usepackage{amssymb}

    12 \usepackage{hyperref}

    13 \usepackage[english]{babel} \usepackage{ae,aecompl}

    14 \usepackage{mathpazo,courier,euler} \usepackage[scaled=.95]{helvet}

    15 \usepackage{listings}

    16 \lstset{language=Python, basicstyle=\ttfamily\bfseries,

    17 commentstyle=\color{red}\itshape, stringstyle=\color{darkgreen},

    18 showstringspaces=false, keywordstyle=\color{blue}\bfseries}

    19 

    20 \title{Accessing parts of arrays}

    21 \author{FOSSEE}

    22 \date{}

    23 

    24 \begin{document}

    25 

    26 \maketitle

    27 

    28 

    29 

    30 

    31 

    32 

    33 

    34 

    35 

    36 \begin{frame}

    37 \frametitle{Outline}

    38 \label{sec-1}

    39 

    40 \begin{itemize}

    41 \item Manipulating one and multi dimensional arrays

    42 \item Access and change individual elements

    43 \item Access and change rows and columns

    44 \item Slicing and striding on arrays to access chunks

    45 \item Read images into arrays and manipulations

    46 \end{itemize}

    47 \end{frame}

    48 \begin{frame}[fragile]

    49 \frametitle{Sample Arrays}

    50 \label{sec-2}

    51 

    52 \begin{verbatim}

    53 In []: A = array([12, 23, 34, 45, 56])

    54 

    55 In []: C = array([[11, 12, 13, 14, 15],

    56                   [21, 22, 23, 24, 25],

    57                   [31, 32, 33, 34, 35],

    58                   [41, 42, 43, 44, 45],

    59                   [51, 52, 53, 54, 55]])

    60 \end{verbatim}

    61 \end{frame}

    62 \begin{frame}

    63 \frametitle{Question 1}

    64 \label{sec-3}

    65 

    66   Change the last column of \texttt{C} to zeroes. 

    67 \end{frame}

    68 \begin{frame}[fragile]

    69 \frametitle{Solution 1}

    70 \label{sec-4}

    71 

    72 \begin{verbatim}

    73 In []:  C[:, -1] = 0

    74 \end{verbatim}

    75 \end{frame}

    76 \begin{frame}

    77 \frametitle{Question 2}

    78 \label{sec-5}

    79 

    80   Change \texttt{A} to \texttt{[11, 12, 13, 14, 15]}. 

    81 \end{frame}

    82 \begin{frame}[fragile]

    83 \frametitle{Solution 2}

    84 \label{sec-6}

    85 

    86 \begin{verbatim}

    87 In []:  A[:] = [11, 12, 13, 14, 15]

    88 \end{verbatim}

    89 \end{frame}

    90 \begin{frame}

    91 \frametitle{squares.png}

    92 \label{sec-7}

    93 

    94     \begin{center}

    95       \includegraphics[scale=0.6]{squares}    

    96     \end{center}

    97 \end{frame}

    98 \begin{frame}

    99 \frametitle{Question 3}

   100 \label{sec-8}

   101 

   102 \begin{itemize}

   103 \item obtain \texttt{[22, 23]} from \texttt{C}.

   104 \item obtain \texttt{[11, 21, 31, 41]} from \texttt{C}.

   105 \item obtain \texttt{[21, 31, 41, 0]}.

   106 \end{itemize}

   107 \end{frame}

   108 \begin{frame}[fragile]

   109 \frametitle{Solution 3}

   110 \label{sec-9}

   111 

   112 \begin{verbatim}

   113 In []:  C[1, 1:3]

   114 In []:  C[0:4, 0]

   115 In []:  C[1:5, 0]

   116 \end{verbatim}

   117 \end{frame}

   118 \begin{frame}

   119 \frametitle{Question 4}

   120 \label{sec-10}

   121 

   122   Obtain \texttt{[[23, 24], [33, -34]]} from \texttt{C}

   123 \end{frame}

   124 \begin{frame}[fragile]

   125 \frametitle{Solution 4}

   126 \label{sec-11}

   127 

   128 \begin{verbatim}

   129 In []:  C[1:3, 2:4]

   130 \end{verbatim}

   131 \end{frame}

   132 \begin{frame}

   133 \frametitle{Question 5}

   134 \label{sec-12}

   135 

   136   Obtain the square in the center of the image

   137 \end{frame}

   138 \begin{frame}[fragile]

   139 \frametitle{Solution 5}

   140 \label{sec-13}

   141 

   142 \begin{verbatim}

   143 In []: imshow(I[75:225, 75:225])

   144 \end{verbatim}

   145 \end{frame}

   146 \begin{frame}[fragile]

   147 \frametitle{Question 6}

   148 \label{sec-14}

   149 

   150   Obtain the following

   151 \begin{verbatim}

   152 [[12, 0], [42, 0]]

   153 [[12, 13, 14], [0, 0, 0]]

   154 \end{verbatim}

   155 \end{frame}

   156 \begin{frame}[fragile]

   157 \frametitle{Solution 6}

   158 \label{sec-15}

   159 

   160 \begin{verbatim}

   161 In []: C[::3, 1::3]

   162 In []: C[::4, 1:4]

   163 \end{verbatim}

   164 \end{frame}

   165 \begin{frame}

   166 \frametitle{Summary}

   167 \label{sec-16}

   168 

   169   You should now be able to --

   170 \begin{itemize}

   171 \item Manipulate single \& multi dimensional arrays

   172 

   173 \begin{itemize}

   174 \item Access and change individual elements

   175 \item Access and change rows and columns

   176 \item Slice and stride on arrays

   177 \end{itemize}

   178 

   179 \item Read images into arrays and manipulate them.

   180 \end{itemize}

   181 \end{frame}

   182 \begin{frame}

   183 \frametitle{Thank you!}

   184 \label{sec-17}

   185 

   186   \begin{block}{}

   187   \begin{center}

   188   This spoken tutorial has been produced by the

   189   \textcolor{blue}{FOSSEE} team, which is funded by the 

   190   \end{center}

   191   \begin{center}

   192     \textcolor{blue}{National Mission on Education through \\

   193       Information \& Communication Technology \\ 

   194       MHRD, Govt. of India}.

   195   \end{center}  

   196   \end{block}

   197 \end{frame}

   198 

   199 \end{document}