1 % Created 2010-11-02 Tue 17:47

     2 \documentclass[presentation]{beamer}

     3 \usepackage[latin1]{inputenc}

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     5 \usepackage{fixltx2e}

     6 \usepackage{graphicx}

     7 \usepackage{longtable}

     8 \usepackage{float}

     9 \usepackage{wrapfig}

    10 \usepackage{soul}

    11 \usepackage{textcomp}

    12 \usepackage{marvosym}

    13 \usepackage{wasysym}

    14 \usepackage{latexsym}

    15 \usepackage{amssymb}

    16 \usepackage{hyperref}

    17 \tolerance=1000

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

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

    20 \usepackage{listings}

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

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

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

    24 \providecommand{\alert}[1]{\textbf{#1}}

    25 

    26 \title{Accessing parts of arrays}

    27 \author{FOSSEE}

    28 \date{}

    29 

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

    31 \begin{document}

    32 

    33 \maketitle

    34 

    35 

    36 

    37 

    38 

    39 

    40 

    41 

    42 

    43 \begin{frame}

    44 \frametitle{Outline}

    45 \label{sec-1}

    46 

    47 \begin{itemize}

    48 \item Manipulating one and multi dimensional arrays

    49 \item Access and change individual elements

    50 \item Access and change rows and columns

    51 \item Slicing and striding on arrays to access chunks

    52 \item Read images into arrays and manipulations

    53 \end{itemize}

    54 \end{frame}

    55 \begin{frame}[fragile]

    56 \frametitle{Sample Arrays}

    57 \label{sec-2}

    58 

    59 \lstset{language=Python}

    60 \begin{lstlisting}

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

    62 

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

    64                   [21, 22, 23, 24, 25],

    65                   [31, 32, 33, 34, 35],

    66                   [41, 42, 43, 44, 45],

    67                   [51, 52, 53, 54, 55]])

    68 \end{lstlisting}

    69 \end{frame}

    70 \begin{frame}

    71 \frametitle{Question 1}

    72 \label{sec-3}

    73 

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

    75 \end{frame}

    76 \begin{frame}[fragile]

    77 \frametitle{Solution 1}

    78 \label{sec-4}

    79 

    80 \lstset{language=Python}

    81 \begin{lstlisting}

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

    83 \end{lstlisting}

    84 \end{frame}

    85 \begin{frame}

    86 \frametitle{Question 2}

    87 \label{sec-5}

    88 

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

    90 \end{frame}

    91 \begin{frame}[fragile]

    92 \frametitle{Solution 2}

    93 \label{sec-6}

    94 

    95 \lstset{language=Python}

    96 \begin{lstlisting}

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

    98 \end{lstlisting}

    99 \end{frame}

   100 \begin{frame}

   101 \frametitle{squares.png}

   102 \label{sec-7}

   103 

   104     \begin{center}

   105       \includegraphics[scale=0.6]{squares}    

   106     \end{center}

   107 \end{frame}

   108 \begin{frame}

   109 \frametitle{Question 3}

   110 \label{sec-8}

   111 

   112 \begin{itemize}

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

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

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

   116 \end{itemize}

   117 \end{frame}

   118 \begin{frame}[fragile]

   119 \frametitle{Solution 3}

   120 \label{sec-9}

   121 

   122 \lstset{language=Python}

   123 \begin{lstlisting}

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

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

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

   127 \end{lstlisting}

   128 \end{frame}

   129 \begin{frame}

   130 \frametitle{Question 4}

   131 \label{sec-10}

   132 

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

   134 \end{frame}

   135 \begin{frame}[fragile]

   136 \frametitle{Solution 4}

   137 \label{sec-11}

   138 

   139 \lstset{language=Python}

   140 \begin{lstlisting}

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

   142 \end{lstlisting}

   143 \end{frame}

   144 \begin{frame}

   145 \frametitle{Question 5}

   146 \label{sec-12}

   147 

   148   Obtain the square in the center of the image

   149 \end{frame}

   150 \begin{frame}[fragile]

   151 \frametitle{Solution 5}

   152 \label{sec-13}

   153 

   154 \lstset{language=Python}

   155 \begin{lstlisting}

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

   157 \end{lstlisting}

   158 \end{frame}

   159 \begin{frame}[fragile]

   160 \frametitle{Question 6}

   161 \label{sec-14}

   162 

   163   Obtain the following

   164 \lstset{language=Python}

   165 \begin{lstlisting}

   166 [[12, 0], [42, 0]]

   167 [[12, 13, 14], [0, 0, 0]]

   168 \end{lstlisting}

   169 \end{frame}

   170 \begin{frame}[fragile]

   171 \frametitle{Solution 6}

   172 \label{sec-15}

   173 

   174 \lstset{language=Python}

   175 \begin{lstlisting}

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

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

   178 \end{lstlisting}

   179 \end{frame}

   180 \begin{frame}

   181 \frametitle{Summary}

   182 \label{sec-16}

   183 

   184   You should now be able to --

   185 \begin{itemize}

   186 \item Manipulate single \& multi dimensional arrays

   187 

   188 \begin{itemize}

   189 \item Access and change individual elements

   190 \item Access and change rows and columns

   191 \item Slice and stride on arrays

   192 \end{itemize}

   193 

   194 \item Read images into arrays and manipulate them.

   195 \end{itemize}

   196 \end{frame}

   197 \begin{frame}

   198 \frametitle{Thank you!}

   199 \label{sec-17}

   200 

   201   \begin{block}{}

   202   \begin{center}

   203   This spoken tutorial has been produced by the

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

   205   \end{center}

   206   \begin{center}

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

   208       Information \& Communication Technology \\ 

   209       MHRD, Govt. of India}.

   210   \end{center}  

   211   \end{block}

   212 \end{frame}

   213 

   214 \end{document}