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#+LaTeX_CLASS: beamer
#+LaTeX_CLASS_OPTIONS: [presentation]
#+BEAMER_FRAME_LEVEL: 1
#+BEAMER_HEADER_EXTRA: \usetheme{Antibes}\usecolortheme{lily}\useoutertheme{infolines}\setbeamercovered{transparent}
#+COLUMNS: %45ITEM %10BEAMER_env(Env) %10BEAMER_envargs(Env Args) %4BEAMER_col(Col) %8BEAMER_extra(Extra)
#+PROPERTY: BEAMER_col_ALL 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 :ETC
#+LaTeX_CLASS: beamer
#+LaTeX_CLASS_OPTIONS: [presentation]
#+LaTeX_HEADER: \usepackage[english]{babel} \usepackage{ae,aecompl}
#+LaTeX_HEADER: \usepackage{mathpazo,courier,euler} \usepackage[scaled=.95]{helvet}
#+LaTeX_HEADER: \usepackage{listings}
#+LaTeX_HEADER:\lstset{language=Python, basicstyle=\ttfamily\bfseries,
#+LaTeX_HEADER: commentstyle=\color{red}\itshape, stringstyle=\color{darkgreen},
#+LaTeX_HEADER: showstringspaces=false, keywordstyle=\color{blue}\bfseries}
#+TITLE:
#+AUTHOR: FOSSEE
#+EMAIL:
#+DATE:
#+DESCRIPTION:
#+KEYWORDS:
#+LANGUAGE: en
#+OPTIONS: H:3 num:nil toc:nil \n:nil @:t ::t |:t ^:t -:t f:t *:t <:t
#+OPTIONS: TeX:t LaTeX:nil skip:nil d:nil todo:nil pri:nil tags:not-in-toc
*
#+begin_latex
\begin{center}
\vspace{12pt}
\textcolor{blue}{\huge Getting started with Arrays}
\end{center}
\vspace{18pt}
\begin{center}
\vspace{10pt}
\includegraphics[scale=0.95]{../images/fossee-logo.png}\\
\vspace{5pt}
\scriptsize Developed by FOSSEE Team, IIT-Bombay. \\
\scriptsize Funded by National Mission on Education through ICT\\
\scriptsize MHRD,Govt. of India\\
\includegraphics[scale=0.30]{../images/iitb-logo.png}\\
\end{center}
#+end_latex
* Objectives
At the end of this tutorial, you will be able to,
- Access and change individual elements of arrays, both one
dimensional and multi-dimensional.
- Access and change rows and columns of arrays.
- Access and change other chunks from an array, using slicing
and striding.
- Read images into arrays and perform processing on them, using
simple array manipulations.
* Pre-requisite
- Spoken tutorial on "Getting started with Arrays".
* Sample Arrays
#+begin_src python
In []: A = array([12, 23, 34, 45, 56])
In []: C = array([[11, 12, 13, 14, 15],
[21, 22, 23, 24, 25],
[31, 32, 33, 34, 35],
[41, 42, 43, 44, 45],
[51, 52, 53, 54, 55]])
#+end_src
* Exercise 1
Change the last column of ~C~ to zeroes.
* Exercise 2
Change ~A~ to ~[11, 12, 13, 14, 15]~.
* squares.png
#+begin_latex
\begin{center}
\includegraphics[scale=0.6]{squares}
\end{center}
#+end_latex
* Exercise 3
- obtain ~[22, 23]~ from ~C~.
- obtain ~[11, 21, 31, 41]~ from ~C~.
- obtain ~[21, 31, 41, 0]~.
* Exercise 4
Obtain ~[[23, 24], [33, -34]]~ from ~C~
* Exercise 5
Obtain the square in the center of the image
* Exercise 6
Obtain the following
#+begin_src python
[[12, 0], [42, 0]]
[[12, 13, 14], [0, 0, 0]]
#+end_src
* Solution 6
#+begin_src python
In []: C[::3, 1::3]
In []: C[::4, 1:4]
#+end_src
* Summary
In this tutorial, we have learnt to,
- Manipulate single & multi dimensional arrays.
- Access and change individual elements by using their index numbers.
- Access and change rows and columns of arrays by specifying the row
and column numbers.
- Slice and stride on arrays.
- Read images into arrays and manipulate them.
* Evaluation
1. Given the array, ``A = array([12, 15, 18, 21])``, how do we access
the element ``18``?
2. Given the array,
C = array([[10, 11, 12, 13],
[20, 21, 22, 23],
[30, 31, 32, 33],
[40, 41, 42, 43]])
Obtain the elements, ``[[21, 22], [31, 32]]``
3. Given the array,
C = array([[10, 11, 12, 13],
[20, 21, 22, 23]])
Change the array to
C = array([[10, 11, 10, 11],
[20, 21, 20, 21]])
* Solutions
1. A[ 2 ]
2. B[1:3, 1:3]
3. B[:2, 2:] = B[:2, :2]
*
#+begin_latex
\begin{block}{}
\begin{center}
\textcolor{blue}{\Large THANK YOU!}
\end{center}
\end{block}
\begin{block}{}
\begin{center}
For more Information, visit our website\\
\url{http://fossee.in/}
\end{center}
\end{block}
#+end_latex
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