diff options
author | Puneeth Chaganti | 2010-10-13 11:15:37 +0530 |
---|---|---|
committer | Puneeth Chaganti | 2010-10-13 11:15:37 +0530 |
commit | 0a23ec7bac01a403ad4f00b27e0b8a0357368616 (patch) | |
tree | ea5aeb4a121bca49f80e0dce858e87b3006cefff /manipulating-lists | |
parent | 7053b6187cd170b386b3de2e458208759f55ebc3 (diff) | |
parent | be31ddd2dd2772ab91df9e15ceb46d6bf6277400 (diff) | |
download | st-scripts-0a23ec7bac01a403ad4f00b27e0b8a0357368616.tar.gz st-scripts-0a23ec7bac01a403ad4f00b27e0b8a0357368616.tar.bz2 st-scripts-0a23ec7bac01a403ad4f00b27e0b8a0357368616.zip |
Merged heads.
Diffstat (limited to 'manipulating-lists')
-rw-r--r-- | manipulating-lists/quickref.tex | 8 | ||||
-rw-r--r-- | manipulating-lists/script.rst | 196 | ||||
-rw-r--r-- | manipulating-lists/slides.org | 123 | ||||
-rw-r--r-- | manipulating-lists/slides.tex | 106 |
4 files changed, 433 insertions, 0 deletions
diff --git a/manipulating-lists/quickref.tex b/manipulating-lists/quickref.tex new file mode 100644 index 0000000..b26d168 --- /dev/null +++ b/manipulating-lists/quickref.tex @@ -0,0 +1,8 @@ +Creating a linear array:\\ +{\ex \lstinline| x = linspace(0, 2*pi, 50)|} + +Plotting two variables:\\ +{\ex \lstinline| plot(x, sin(x))|} + +Plotting two lists of equal length x, y:\\ +{\ex \lstinline| plot(x, y)|} diff --git a/manipulating-lists/script.rst b/manipulating-lists/script.rst new file mode 100644 index 0000000..6d7d4b2 --- /dev/null +++ b/manipulating-lists/script.rst @@ -0,0 +1,196 @@ +.. Objectives +.. ---------- + +.. Clearly state the objectives of the LO (along with RBT level) + +.. Prerequisites +.. ------------- + +.. 1. getting started with lists +.. 2. +.. 3. + +.. Author : Madhu + Internal Reviewer : + External Reviewer : + Checklist OK? : <put date stamp here, if OK> [2010-10-05] + +Script +------ + +{{{ Show the slide containing the title }}} + +Hello friends. Welcome to this spoken tutorial on Manipulating Lists. + + +{{{ Show the slide containing the outline }}} + +We have already learnt a lot about Lists in Python. In this tutorial, +we will learn more about advanced features of Lists in Python. We will +see in detail how to concatenate two lists, slicing and striding of +lists, methods to sort and reverse the list. + +{{{ Shift to terminal and start ipython }}} + +To begin with let us start ipython, by typing:: + + ipython + +on the terminal + +We already know what Lists are in Python, how to access individual +elements in the list and some of the functions that can be run on the +lists like max, min, sum len and so on. Now let us learn some of the +basic operations that can be performed on Lists. + +We already know how to access individual elements in a List. But what +if we have a scenario where we need to get a part of the entire list +or what we call as a slice of the list? Python supports slicing on +lists. Let us say I have the list:: + + primes = [2, 3, 5, 7, 11, 13, 17, 19, 23, 29] + +To obtain the all the primes between 10 and 20 from the above list of +primes we say:: + + primes[4:8] + +This gives us all the elements in the list starting from the element +with the index 4 which is 11 in our list upto the element with index 8 +in the list but not including the eigth element. So we obtain a slice +starting from 11 upto 19th. It is a very important to remember that +when ever we specify a range of elements in Python the start index is +included and end index is not included. So in the above case, 11 which +was the element with the index 4 was included but 23 which was the +element with index 8 was excluded. + +Generalizing, we can obtain a slice of the list "p" from the index +"start" upto the index "end" but excluding "end" with the following +syntax + +{{{ Show the slide containing p[start:stop] }}} + +By default the slice fetches all the elements between start and stop +including start but not stop. So as to say we obtain all the elements +between start and stop in steps of one. Python also provides us the +functionality to specify the steps in which the slice must be +obtained. Say we have:: + + num = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13] + +If we want to obtain all the odd numbers less than 10 from the list +"num" we have to start from element with index 1 upto the index 10 in +steps of 2:: + + num[1:10:2] + +So if we don't specify the step it is by default 1. Similary there are +default values for start and stop indices as well. If we don't specify +the start index it is implicitly taken as the first element of the +list:: + + num[:10] + +This gives us all the elements from the beginning upto the 10th +element but not including the 10th element in the list "num". Similary +if the stop index is not specified it is implicitly assumed to be the +end of the list, including the last element of the list:: + + num[10:] + +gives all the elements starting from the 10th element in the list +"num" upto the final element including that last element. Now:: + + num[::2] + +gives us all the even numbers in the list "num". + +The other basic operation that we can perform on list is concatenation +of two or more lists. We can combine two lists by using the "plus" +operator. Say we have + +{{{ Read as you type }}}:: + + a = [1, 2, 3, 4] + b = [4, 5, 6, 7] + a + b + +When we concatenate lists using the "plus" operator we get a new +list. We can store this list in a new variable:: + + c = a + b + c + +It is important to observe that the "plus" operator always returns a +new list without touching anything in the existing lists which are the +operands of the concatenation operation. + +We know that list is a collection of data. Whenever we have a +collection we run into situations where we want to start the +collection. Lists support sort method which sorts the list inplace:: + + a = [5, 1, 6, 7, 7, 10] + a.sort() + +Now the contents of the list "a" will be:: + + a + [1, 5, 6, 7, 7, 10] + +Since the sort method sorts the list inplace the original list we had +is overwritten or replaced. We have no way to obtain the original list +back. One way to avoid this is to keep a copy of the original list in +another variable and run the sort method on the list. However Python +also provides a built-in function called sorted which sorts the list +which is passed as an argument to it and returns a new sorted list:: + + a = [5, 1, 6, 7, 7, 10] + sorted(a) + +We can store this sorted list another list variable:: + + sa = sorted(a) + +Similarly to perform certain operations on the list we would like to +reverse the list. Python provides reverse method which again reverses +the list inplace:: + + a = [1, 2, 3, 4, 5] + a.reverse() + +reverses the list "a" and stores the reversed list inplace i.e. in "a" +itself. Lets see the list "a":: + + a + [5, 4, 3, 2, 1] + +But again the original list is lost. If we want to obtain the reverse +of a list keeping the original list intact we can use the Python +built-in function reversed. reversed function returns a new list which +is the reverse of the list which was passed as the argument to the +reversed function:: + + a = [1, 2, 3, 4, 5] + reversed(a) + +We can also store this new reversed list in another list variable. + +{{{ Show summary slide }}} + +This brings us to the end of another session. In this tutorial session +we learnt + + * How to define strings + * Different types of defining a string + * String concatenation and repeatition + * Accessing individual elements of the string + * Immutability of strings + +{{{ Show the "sponsored by FOSSEE" slide }}} + +This tutorial was created as a part of FOSSEE project, NME ICT, MHRD India + +Hope you have enjoyed and found it useful. +Thank you! + + diff --git a/manipulating-lists/slides.org b/manipulating-lists/slides.org new file mode 100644 index 0000000..5d2ce93 --- /dev/null +++ b/manipulating-lists/slides.org @@ -0,0 +1,123 @@ +#+LaTeX_CLASS: beamer +#+LaTeX_CLASS_OPTIONS: [presentation] +#+BEAMER_FRAME_LEVEL: 1 + +#+BEAMER_HEADER_EXTRA: \usetheme{Warsaw}\usecolortheme{default}\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: Accessing parts of arrays +#+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 + +* Outline + - Manipulating one and multi dimensional arrays + - Access and change individual elements + - Access and change rows and columns + - Slicing and striding on arrays to access chunks + - Read images into arrays and manipulations +* 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 +* Question 1 + Change the last column of ~C~ to zeroes. +* Solution 1 + #+begin_src python + In []: C[:, -1] = 0 + #+end_src +* Question 2 + Change ~A~ to ~[11, 12, 13, 14, 15]~. +* Solution 2 + #+begin_src python + In []: A[:] = [11, 12, 13, 14, 15] + #+end_src +* squares.png + #+begin_latex + \begin{center} + \includegraphics[scale=0.6]{squares} + \end{center} + #+end_latex +* Question 3 + - obtain ~[22, 23]~ from ~C~. + - obtain ~[11, 21, 31, 41]~ from ~C~. + - obtain ~[21, 31, 41, 0]~. +* Solution 3 + #+begin_src python + In []: C[1, 1:3] + In []: C[0:4, 0] + In []: C[1:5, 0] + #+end_src +* Question 4 + Obtain ~[[23, 24], [33, -34]]~ from ~C~ +* Solution 4 + #+begin_src python + In []: C[1:3, 2:4] + #+end_src +* Question 5 + Obtain the square in the center of the image +* Solution 5 + #+begin_src python + In []: imshow(I[75:225, 75:225]) + #+end_src +* Question 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 + You should now be able to -- + - Manipulate 1D \& Multi dimensional arrays + - Access and change individual elements + - Access and change rows and columns + - Slice and stride on arrays + - Read images into arrays and manipulate them. +* Thank you! +#+begin_latex + \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_latex + + diff --git a/manipulating-lists/slides.tex b/manipulating-lists/slides.tex new file mode 100644 index 0000000..df1462c --- /dev/null +++ b/manipulating-lists/slides.tex @@ -0,0 +1,106 @@ +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%Tutorial slides on Python. +% +% Author: FOSSEE +% Copyright (c) 2009, FOSSEE, IIT Bombay +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +\documentclass[14pt,compress]{beamer} +%\documentclass[draft]{beamer} +%\documentclass[compress,handout]{beamer} +%\usepackage{pgfpages} +%\pgfpagesuselayout{2 on 1}[a4paper,border shrink=5mm] + +% Modified from: generic-ornate-15min-45min.de.tex +\mode<presentation> +{ + \usetheme{Warsaw} + \useoutertheme{infolines} + \setbeamercovered{transparent} +} + +\usepackage[english]{babel} +\usepackage[latin1]{inputenc} +%\usepackage{times} +\usepackage[T1]{fontenc} + +\usepackage{ae,aecompl} +\usepackage{mathpazo,courier,euler} +\usepackage[scaled=.95]{helvet} + +\definecolor{darkgreen}{rgb}{0,0.5,0} + +\usepackage{listings} +\lstset{language=Python, + basicstyle=\ttfamily\bfseries, + commentstyle=\color{red}\itshape, + stringstyle=\color{darkgreen}, + showstringspaces=false, + keywordstyle=\color{blue}\bfseries} + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% Macros +\setbeamercolor{emphbar}{bg=blue!20, fg=black} +\newcommand{\emphbar}[1] +{\begin{beamercolorbox}[rounded=true]{emphbar} + {#1} + \end{beamercolorbox} +} +\newcounter{time} +\setcounter{time}{0} +\newcommand{\inctime}[1]{\addtocounter{time}{#1}{\tiny \thetime\ m}} + +\newcommand{\typ}[1]{\lstinline{#1}} + +\newcommand{\kwrd}[1]{ \texttt{\textbf{\color{blue}{#1}}} } + +% Title page +\title{Your Title Here} + +\author[FOSSEE] {FOSSEE} + +\institute[IIT Bombay] {Department of Aerospace Engineering\\IIT Bombay} +\date{} + +% DOCUMENT STARTS +\begin{document} + +\begin{frame} + \maketitle +\end{frame} + +\begin{frame}[fragile] + \frametitle{Outline} + \begin{itemize} + \item + \end{itemize} +\end{frame} + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +%% All other slides here. %% +%% The same slides will be used in a classroom setting. %% +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +\begin{frame}[fragile] + \frametitle{Summary} + \begin{itemize} + \item + \end{itemize} +\end{frame} + +\begin{frame} + \frametitle{Thank you!} + \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} |