diff options
Diffstat (limited to 'day1/Session-4.tex~')
| -rwxr-xr-x | day1/Session-4.tex~ | 378 |
1 files changed, 378 insertions, 0 deletions
diff --git a/day1/Session-4.tex~ b/day1/Session-4.tex~ new file mode 100755 index 0000000..ba2a062 --- /dev/null +++ b/day1/Session-4.tex~ @@ -0,0 +1,378 @@ +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% Tutorial slides on Python. +% +% Author: Prabhu Ramachandran <prabhu at aero.iitb.ac.in> +% Copyright (c) 2005-2008, Prabhu Ramachandran +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +\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{split} + \setbeamercovered{transparent} +} + +\usepackage[english]{babel} +\usepackage[latin1]{inputenc} +%\usepackage{times} +\usepackage[T1]{fontenc} + +% Taken from Fernando's slides. +\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]{\texttt{#1}} + +\newcommand{\kwrd}[1]{ \texttt{\textbf{\color{blue}{#1}}} } + +%%% This is from Fernando's setup. +% \usepackage{color} +% \definecolor{orange}{cmyk}{0,0.4,0.8,0.2} +% % Use and configure listings package for nicely formatted code +% \usepackage{listings} +% \lstset{ +% language=Python, +% basicstyle=\small\ttfamily, +% commentstyle=\ttfamily\color{blue}, +% stringstyle=\ttfamily\color{orange}, +% showstringspaces=false, +% breaklines=true, +% postbreak = \space\dots +% } + + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% Title page +\title[Basic Python]{Python:\\Advanced Python data structures, Functions and Debugging} + +\author[FOSSEE Team] {Asokan Pichai\\Prabhu Ramachandran} + +\institute[IIT Bombay] {Department of Aerospace Engineering\\IIT Bombay} +\date[] {10, October 2009} +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% + +%\pgfdeclareimage[height=0.75cm]{iitmlogo}{iitmlogo} +%\logo{\pgfuseimage{iitmlogo}} + + +%% Delete this, if you do not want the table of contents to pop up at +%% the beginning of each subsection: +\AtBeginSubsection[] +{ + \begin{frame}<beamer> + \frametitle{Outline} + \tableofcontents[currentsection,currentsubsection] + \end{frame} +} + + +% If you wish to uncover everything in a step-wise fashion, uncomment +% the following command: +%\beamerdefaultoverlayspecification{<+->} + +%\includeonlyframes{current,current1,current2,current3,current4,current5,current6} + +%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% +% DOCUMENT STARTS +\begin{document} + +\begin{frame} + \titlepage +\end{frame} + +\section{Python} + +\subsection{Dictionary} +\begin{frame}{Dictionary} + \begin{itemize} + \item aka associative arrays, key-value pairs, hashmaps, hashtables \ldots + \item \typ{ d = \{ ``Hitchhiker's guide'' : 42, ``Terminator'' : ``I'll be back''\}} + \item lists and tuples index: 0 \ldots n + \item dictionaries index using strings + \item aka key-value pairs + \item what can be keys? + \end{itemize} +\end{frame} + +\begin{frame}{Dictionary \ldots } + \begin{itemize} + \item \alert{Unordered} + \begin{block}{Standard usage} + for key in dict:\\ + <use> dict[key] \# => value + \end{block} + \item \typ{d.keys()} returns a list + \item can we have duplicate keys? + \end{itemize} + \inctime{5} +\end{frame} + +\begin{frame} {Problem Set 2.1} + \begin{description} +\item[2.1.1] You are given date strings of the form ``29, Jul 2009'', or ``4 January 2008''. In other words a number a string and another number, with a comma sometimes separating the items.Write a function that takes such a string and returns a tuple (yyyy, mm, dd) where all three elements are ints. + \item[2.1.2] Count word frequencies in a file. + \item[2.1.3] Find the most used Python keywords in your Python code (import keyword). +\end{description} + +\inctime{10} +\end{frame} + +\subsection{Set} +\begin{frame}[fragile] + \frametitle{Set} + \begin{itemize} + \item Simplest container, mutable + \item No ordering, no duplicates + \item usual suspects: union, intersection, subset \ldots + \item >, >=, <, <=, in, \ldots + \end{itemize} + \begin{lstlisting} +>>> f10 = set([1,2,3,5,8]) +>>> p10 = set([2,3,5,7]) +>>> f10|p10 +set([1, 2, 3, 5, 7, 8]) +>>> f10&p10 +set([2, 3, 5]) +>>> f10-p10 +set([8, 1]) +\end{lstlisting} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Set} + \begin{lstlisting} +>>> p10-f10, f10^p10 +set([7]), set([1, 7, 8]) +>>> set([2,3]) < p10 +True +>>> set([2,3]) <= p10 +True +>>> 2 in p10 +True +>>> 4 in p10 +False +>>> len(f10) +5 +\end{lstlisting} +\inctime{5} +\end{frame} + + +\begin{frame} + \frametitle{Problem set 2.2} + \begin{description} + \item[2.2.1] Given a dictionary of the names of students and their marks, identify how many duplicate marks are there? and what are these? + \item[2.2.2] Given a string of the form ``4-7, 9, 12, 15'' find the numbers missing in this list for a given range. +\end{description} +\inctime{10} +\end{frame} + +\subsection{Functions Reloaded!} +\begin{frame}[fragile] + \frametitle{Advanced functions} + \begin{itemize} + \item default args + \item var args + \item keyword args + \item scope + \item \typ{global} + \end{itemize} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Functions: default arguments} + \small + \begin{lstlisting} +def ask_ok(prompt, retries=4, + complaint='Yes or no!'): + while True: + ok = raw_input(prompt) + if ok in ('y', 'ye', 'yes'): + return True + if ok in ('n', 'no', 'nop', + 'nope'): + return False + retries = retries - 1 + if retries < 0: + raise IOError, 'bad user' + print complaint + \end{lstlisting} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Functions: keyword arguments} + \small + \begin{lstlisting} +def parrot(voltage, state='a stiff', + action='voom', type='Royal Blue'): + print "-- This parrot wouldn't", action, + print "if you supply", voltage, "Volts." + print "-- Lovely plumage, the", type + print "-- It's", state, "!" + +parrot(1000) +parrot(action = 'VOOOOOM', voltage = 1000000) +parrot('a thousand', + state = 'pushing up the daisies') +parrot('a million', 'bereft of life', 'jump') +\end{lstlisting} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Functions: arbitrary argument lists} + \begin{itemize} + \item Arbitrary number of arguments using \verb+*args+ or + \verb+*whatever+ + \item Keyword arguments using \verb+**kw+ + \item Given a tuple/dict how do you call a function? + \begin{itemize} + \item Using argument unpacking + \item For positional arguments: \verb+foo(*[5, 10])+ + \item For keyword args: \verb+foo(**{'a':5, 'b':10})+ + \end{itemize} + \end{itemize} +\end{frame} + + \begin{frame}[fragile] +\begin{lstlisting} +def foo(a=10, b=100): + print a, b +def func(*args, **keyword): + print args, keyword +# Unpacking: +args = [5, 10] +foo(*args) +kw = {'a':5, 'b':10} +foo(**kw) +\end{lstlisting} + \inctime{15} +\end{frame} + +\subsection{Functional programming} +\begin{frame}[fragile] + \frametitle{Functional programming} +What is the basic idea?\\ +Why is it interesting?\\ +\typ{map, reduce, filter}\\ +list comprehension\\ +generators + \inctime{15} +\end{frame} + +\subsection{Debugging} +\begin{frame}[fragile] + \frametitle{Errors} + \begin{lstlisting} +>>> while True print 'Hello world' + File "<stdin>", line 1, in ? + while True print 'Hello world' + ^ +SyntaxError: invalid syntax +\end{lstlisting} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Exceptions} + \begin{lstlisting} +>>> print spam +Traceback (most recent call last): + File "<stdin>", line 1, in <module> +NameError: name 'spam' is not defined + +>>> 1 / 0 +Traceback (most recent call last): + File "<stdin>", line 1, in <module> +ZeroDivisionError: integer division +or modulo by zero +\end{lstlisting} +\end{frame} + +\begin{frame}[fragile] + \frametitle{Debugging effectively} + + \begin{itemize} + \item \kwrd{print} based strategy + \item Process: Hypothesis, test, refine, rinse-repeat + \item Using \typ{\%debug} and \typ{\%pdb} in IPython + \end{itemize} + \inctime{15} +\end{frame} + +\begin{frame}[fragile] +\frametitle{Debugging: example} +\small +\begin{lstlisting} +>>> import pdb +>>> import mymodule +>>> pdb.run('mymodule.test()') +> <string>(1)<module>() +(Pdb) continue +Traceback (most recent call last): + File "<stdin>", line 1, in <module> + File "/usr/lib/python2.6/pdb.py", line 1207, in run + Pdb().run(statement, globals, locals) + File "/usr/lib/python2.6/bdb.py", line 368, in run + exec cmd in globals, locals + File "<string>", line 1, in <module> + File "mymodule.py", line 2, in test + print spam +NameError: global name 'spam' is not defined +\end{lstlisting} +\end{frame} + +\begin{frame}[fragile] +\frametitle{Debugging in IPython} +\small +\begin{lstlisting} +In [1]: %pdb +Automatic pdb calling has been turned ON +In [2]: import mymodule +In [3]: mymodule.test() +---------------------------------------------- +NameError Traceback (most recent call last) +/media/python/iitb/workshops/day1/<ipython console> in <module>() +/media/python/iitb/workshops/day1/mymodule.pyc in test() + 1 def test(): +----> 2 print spam +NameError: global name 'spam' is not defined +> /media/python/iitb/workshops/day1/mymodule.py(2)test() + 0 print spam +ipdb> +\end{lstlisting} +\end{frame} + +\begin{frame}[fragile] +\frametitle{Debugging: Exercise} +\end{frame} + +\end{document} |