diff -r 88a01948450d -r d33698326409 getting-started-with-arrays/slides.tex --- a/getting-started-with-arrays/slides.tex Wed Nov 17 23:24:57 2010 +0530 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,284 +0,0 @@ -% Created 2010-11-07 Sun 15:18 -\documentclass[presentation]{beamer} -\usepackage[latin1]{inputenc} -\usepackage[T1]{fontenc} -\usepackage{fixltx2e} -\usepackage{graphicx} -\usepackage{longtable} -\usepackage{float} -\usepackage{wrapfig} -\usepackage{soul} -\usepackage{t1enc} -\usepackage{textcomp} -\usepackage{marvosym} -\usepackage{wasysym} -\usepackage{latexsym} -\usepackage{amssymb} -\usepackage{hyperref} -\tolerance=1000 -\usepackage[english]{babel} \usepackage{ae,aecompl} -\usepackage{mathpazo,courier,euler} \usepackage[scaled=.95]{helvet} -\usepackage{listings} -\lstset{language=Python, basicstyle=\ttfamily\bfseries, -commentstyle=\color{red}\itshape, stringstyle=\color{darkgreen}, -showstringspaces=false, keywordstyle=\color{blue}\bfseries} -\providecommand{\alert}[1]{\textbf{#1}} - -\title{Getting started with arrays} -\author{FOSSEE} -\date{} - -\usetheme{Warsaw}\usecolortheme{default}\useoutertheme{infolines}\setbeamercovered{transparent} -\begin{document} - -\maketitle - - - - - - - - - -\begin{frame} -\frametitle{Outline} -\label{sec-1} - -\begin{itemize} -\item Arrays - -\begin{itemize} -\item why arrays over lists -\end{itemize} - -\item Creating arrays -\item Array operations -\end{itemize} -\end{frame} -\begin{frame} -\frametitle{Overview of Arrays} -\label{sec-2} - -\begin{itemize} -\item Arrays are homogeneous data structures. - -\begin{itemize} -\item elements have to the same data type -\end{itemize} - -\item Arrays are faster compared to lists - -\begin{itemize} -\item at least \emph{80-100 times} faster than lists -\end{itemize} - -\end{itemize} -\end{frame} -\begin{frame}[fragile] -\frametitle{Creating Arrays} -\label{sec-3} - -\begin{itemize} -\item Creating a 1-dimensional array -\end{itemize} - -\begin{verbatim} - In []: a1 = array([1, 2, 3, 4]) -\end{verbatim} - - \texttt{[1, 2, 3, 4]} is a list. -\end{frame} -\begin{frame}[fragile] -\frametitle{Creating two-dimensional array} -\label{sec-4} - -\begin{itemize} -\item Creating a 2-dimensional array -\end{itemize} - -\begin{verbatim} - In []: a2 = array([[1,2,3,4],[5,6,7,8]]) -\end{verbatim} - - here we convert a list of lists to an array making a 2-d array. -\begin{itemize} -\item Easier method of creating array with consecutive elements. -\end{itemize} - -\begin{verbatim} - In []: ar = arange(1,9) -\end{verbatim} -\end{frame} -\begin{frame}[fragile] -\frametitle{\texttt{reshape()} method} -\label{sec-5} - -\begin{itemize} -\item To reshape an array -\end{itemize} - -\begin{verbatim} - In []: ar.reshape(2, 4) - In []: ar.reshape(4, 2) - In []: ar = ar.reshape(2, 4) -\end{verbatim} -\end{frame} -\begin{frame}[fragile] -\frametitle{Creating \texttt{array} from \texttt{list}.} -\label{sec-6} - -\begin{itemize} -\item \texttt{array()} method accepts list as argument -\item Creating a list -\begin{verbatim} - In []: l1 = [1, 2, 3, 4] -\end{verbatim} - -\item Creating an array -\begin{verbatim} - In []: a3 = array(l1) -\end{verbatim} - -\end{itemize} -\end{frame} -\begin{frame} -\frametitle{Exercise 1} -\label{sec-7} - - Create a 3-dimensional array of the order (2, 2, 4). -\end{frame} -\begin{frame}[fragile] -\frametitle{\texttt{.shape} of array} -\label{sec-8} - -\begin{itemize} -\item \texttt{.shape} - To find the shape of the array -\begin{verbatim} - In []: a1.shape -\end{verbatim} - -\item \texttt{.shape} - returns a tuple of shape -\end{itemize} -\end{frame} -\begin{frame} -\frametitle{Exercise 2} -\label{sec-9} - - Find out the shape of the other arrays(a2, a3, ar) that we have created. -\end{frame} -\begin{frame}[fragile] -\frametitle{Homogeneous data} -\label{sec-10} - -\begin{itemize} -\item All elements in array should be of same type -\begin{verbatim} - In []: a4 = array([1,2,3,'a string']) -\end{verbatim} - -\end{itemize} -\end{frame} -\begin{frame}[fragile] -\frametitle{Implicit type casting} -\label{sec-11} - -\begin{verbatim} - In []: a4 -\end{verbatim} - - All elements are type casted to string type -\end{frame} -\begin{frame} -\frametitle{\texttt{identity()}, \texttt{zeros()} methods} -\label{sec-12} - -\begin{itemize} -\item \texttt{identity(n)} - Creates an identity matrix, a square matrix of order (n, n) with diagonal elements 1 and others 0. -\item \texttt{zeros((m, n))} - Creates an \texttt{m X n} matrix with all elements 0. -\end{itemize} -\end{frame} -\begin{frame} -\frametitle{Learning exercise} -\label{sec-13} - -\begin{itemize} -\item Find out about - -\begin{itemize} -\item \texttt{zeros\_like()} -\item \texttt{ones()} -\item \texttt{ones\_like()} -\end{itemize} - -\end{itemize} -\end{frame} -\begin{frame} -\frametitle{Array operations} -\label{sec-14} - -\begin{itemize} -\item \texttt{a1 * 2} - returns a new array with all elements of \texttt{a1} multiplied by \texttt{2}. - -\begin{itemize} -\item Similarly \texttt{+}, \texttt{-} \& \texttt{/}. -\end{itemize} - -\item \texttt{a1 + 2} - returns a new array with all elements of \texttt{a1} summed with \texttt{2}. -\item \texttt{a1 += 2} - adds \texttt{2} to all elements of array \texttt{a1}. - -\begin{itemize} -\item Similarly \texttt{-=}, \texttt{*=} \& \texttt{/=}. -\end{itemize} - -\item \texttt{a1 + a2} - does elements-wise addition. - -\begin{itemize} -\item Similarly \texttt{-}, \texttt{*} \& \texttt{/}. -\end{itemize} - -\item \texttt{a1 * a2} - does element-wise multiplication -\end{itemize} - - - \textbf{Note} - array(A) * array(B) does element wise multiplication and not matrix multiplication -\end{frame} -\begin{frame} -\frametitle{Summary} -\label{sec-15} - - In this tutorial we covered, -\begin{itemize} -\item Basics of arrays -\item Creating arrays -\item Arrays from lists -\item Basic array operations -\end{itemize} -\end{frame} -\begin{frame} -\frametitle{Thank you!} -\label{sec-16} - - \begin{block}{} - \begin{center} - This spoken tutorial has been produced by the - \textcolor{blue}{FOSSEE} team, which is funded by the - \end{center} - \begin{center} - \textcolor{blue}{National Mission on Education through \\ - Information \& Communication Technology \\ - MHRD, Govt. of India}. - \end{center} - \end{block} -\end{frame} - -\end{document}