%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%Tutorial slides on Python.
%
% Author: Prabhu Ramachandran <prabhu at aero.iitb.ac.in>
% Copyright (c) 2005-2009, Prabhu Ramachandran
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% Taken from Fernando's slides.
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\usepackage{listings}
\lstset{language=Python,
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    commentstyle=\color{red}\itshape,
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% Title page
\title[Basic Python]{Python:\\A formal approach}

\author[FOSSEE Team] {The FOSSEE Group}

\institute[IIT Bombay] {Department of Aerospace Engineering\\IIT Bombay}
\date[] {1, November 2009\\Day 2, Session 1}
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%\pgfdeclareimage[height=0.75cm]{iitmlogo}{iitmlogo}
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%% 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}
}

\AtBeginSection[]
{
  \begin{frame}<beamer>
    \frametitle{Outline}
    \tableofcontents[currentsection,currentsubsection]
  \end{frame}
}

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% DOCUMENT STARTS
\begin{document}

\begin{frame}
  \titlepage
\end{frame}

\begin{frame}
  \frametitle{Outline}
  \tableofcontents
  % You might wish to add the option [pausesections]
\end{frame}

\section{Data types}

\begin{frame}
  \frametitle{Primitive Data types}
  \begin{itemize}
    \item Numbers: float, int, complex
    \item Strings
    \item Boolean
  \end{itemize}
\end{frame}

\subsection{Numbers}
\begin{frame}[fragile]
  \frametitle{Numbers}
  \begin{itemize}
    \item \kwrd{int}\\ Any whole number is an \kwrd{int}, no matter what the size!
  \begin{lstlisting}
In [1]: a = 13

In [2]: b = 99999999999999999999
  \end{lstlisting}
    \item \kwrd{float}
  \begin{lstlisting}
In [3]: fl = 3.141592
  \end{lstlisting}
  \end{itemize}
\end{frame}

\begin{frame}[fragile]
\frametitle{Complex numbers}
  \begin{lstlisting}
In [1]: cplx = 3+4j

In [2]: abs(cplx)
Out[2]: 5.0

In [3]: cplx.imag
Out[3]: 4.0

In [4]: cplx.real
Out[4]: 3.0
  \end{lstlisting}
\end{frame}

\subsection{Boolean}
\begin{frame}[fragile]
  \frametitle{Boolean}
  \begin{lstlisting}
In [1]: t = True

In [2]: f = not t
Out[2]: False

In [3]: f or t
Out[3]: True

In [4]: f and t
Out[4]: False
  \end{lstlisting}
\end{frame}

\subsection{Strings}

\begin{frame}[fragile]
  \frametitle{Strings}
Strings were introduced previously, let us now look at them in a little more detail.
  \begin{lstlisting}
In [1]: w = "hello"

In [2]: print w[0] + w[2] + w[-1]
Out[2]: hlo

In [3]: len(w) # guess what
Out[3]: 5
  \end{lstlisting}
\end{frame}

\begin{frame}[fragile]
  \frametitle{Strings \ldots}
  \begin{lstlisting}
In [1]: w[0] = 'H' # Can't do that!
--------------------------------------------
TypeError  Traceback (most recent call last)

/<ipython console> in <module>()

TypeError: 'str' object does not
         support item assignment
  \end{lstlisting}
\end{frame}

\begin{frame}[fragile]
  \frametitle{String methods}
  \begin{lstlisting}
In [1]: a = 'Hello World'
In [2]: a.startswith('Hell')
Out[2]: True

In [3]: a.endswith('ld')
Out[3]: True

In [4]: a.upper()
Out[4]: 'HELLO WORLD'

In [5]: a.lower()
Out[5]: 'hello world'
  \end{lstlisting}
\end{frame}

\begin{frame}[fragile]
\frametitle{Still with strings}
  \begin{itemize}
    \item We saw split() yesterday
    \item join() is the opposite of split()
  \end{itemize}
  \begin{lstlisting}
In [1]: ''.join(['a', 'b', 'c'])
Out[1]: 'abc'
  \end{lstlisting}
\end{frame}

\begin{frame}[fragile]
\frametitle{String formatting}
  \begin{lstlisting}
In [1]: x, y = 1, 1.234

In [2]: 'x is %s, y is %s' %(x, y)
Out[2]: 'x is 1, y is 1.234'
  \end{lstlisting}
\emphbar{
\url{http://docs.python.org/library/stdtypes.html}\\
}
\inctime{10}
\end{frame}

\section{Operators}
\begin{frame}[fragile]
  \frametitle{Arithematic operators}
  \begin{lstlisting}
In [1]: 1786 % 12
Out[1]: 10

In [2]: 3124 * 126789
Out[2]: 396088836

In [3]: a = 3124 * 126789

In [4]: big = 1234567891234567890 ** 3

In [5]: verybig = big * big * big * big
  \end{lstlisting}
\end{frame}

\begin{frame}[fragile]
  \frametitle{Arithematic operators \ldots}
  \begin{lstlisting}
In [1]: 17/2
Out[1]: 8

In [2]: 17/2.0
Out[2]: 8.5

In [3]: 17.0/2
Out[3]: 8.5

In [4]: 17.0/8.5
Out[4]: 2.0
  \end{lstlisting}
\end{frame}

\begin{frame}[fragile]
  \frametitle{String operations}
  \begin{lstlisting}
In [1]: s = 'Hello '

In [2]: p = 'World'

In [3]: s + p 
Out[3]: 'Hello World'

In [4]: s * 12 
Out[4]: 'Hello Hello Hello Hello ...'
  \end{lstlisting}
\end{frame}

\begin{frame}[fragile]
  \frametitle{String operations \ldots}
  \begin{lstlisting}
In [1]: s * s
--------------------------------------------
TypeError  Traceback (most recent call last)

/<ipython console> in <module>()

TypeError: can't multiply sequence by
                non-int of type 'str'
  \end{lstlisting}
\end{frame}

\begin{frame}[fragile]
  \frametitle{Relational and logical operators}
  \begin{lstlisting}
In [1]: pos, zer, neg = 1, 0, -1
In [2]: pos == neg
Out[2]: False

In [3]: pos >= neg
Out[3]: True

In [4]: neg < zer < pos
Out[4]: True

In [5]: pos + neg != zer
Out[5]: False
  \end{lstlisting}
\inctime{5}
\end{frame}

\begin{frame}[fragile]
  \frametitle{Built-ins}
  \begin{lstlisting}
In [1]: int(17/2.0)
Out[1]: 8

In [2]: float(17/2)  # Recall
Out[2]: 8.0

In [3]: str(17/2.0)
Out[3]: '8.5'

In [4]: round( 7.5 )
Out[4]: 8.0
  \end{lstlisting}
\end{frame}

\begin{frame}[fragile]
  \frametitle{Odds and ends}
  \begin{itemize}
    \item Case sensitive
    \item Dynamically typed $\Rightarrow$ need not specify a type
      \begin{lstlisting}
In [1]: a = 1
In [2]: a = 1.1
In [3]: a = "Now I am a string!"
      \end{lstlisting}
    \item Comments:
      \begin{lstlisting}
In [4]: a = 1  # In-line comments
In [5]: # Comment in a line to itself.
In [6]: a = "# This is not a comment!"
      \end{lstlisting}
  \end{itemize}
  \inctime{15}
\end{frame}

\begin{frame}[fragile] \frametitle{A question of good style}
  \begin{lstlisting}
    amount = 12.68
    denom = 0.05
    nCoins = round(amount/denom)
    rAmount = nCoins * denom
  \end{lstlisting}
  \pause
  \begin{block}{Style Rule \#1}
    Naming is 80\% of programming
  \end{block}
\end{frame}

\begin{frame}
  {A classic problem}
  \begin{block}
    {Interchange values}
    How to interchange values of two variables? 
  \end{block}
  \pause
  \begin{block}{Note:}
    This Python idiom works for all types of variables.\\
They need not be of the same type!
  \end{block}
  \inctime{10}
\end{frame}

\section{Simple IO}
\begin{frame}{Simple IO}
  \begin{block}
    {Console Input}
    \texttt{raw\_input()} waits for user input.\\Prompt string is optional.\\
    All keystrokes are Strings!\\\texttt{int()} converts string to int.
  \end{block}
  \begin{block}
    {Console output}
    \texttt{print} is straight forward. Note the distinction between \texttt{print x} and \texttt{print x,}
  \end{block}
\end{frame}

\section{Control flow}
\begin{frame}
  \frametitle{Control flow constructs}  
  \begin{itemize}
  \item \kwrd{if/elif/else}: branching
  \item \kwrd{while}: looping
  \item \kwrd{for}: iterating 
  \item \kwrd{break, continue}: modify loop 
  \item \kwrd{pass}: syntactic filler
  \end{itemize}
\end{frame}

\subsection{Basic Conditional flow}
\begin{frame}[fragile]
  \frametitle{\typ{If...elif...else} example}
\begin{lstlisting}
x = int(raw_input("Enter an integer:"))
if x < 0:
     print 'Be positive!'
elif x == 0:
     print 'Zero'
elif x == 1:
     print 'Single'
else:
     print 'More'
\end{lstlisting}
\end{frame}

\subsection{Basic Looping}
\begin{frame}[fragile]
  \frametitle{\typ{while}}
Example: Fibonacci series
  \begin{lstlisting}
# the sum of two elements
# defines the next
a, b = 0, 1
while b < 10:
    print b,
    a, b = b, a + b 
\end{lstlisting}
\typ{1 1 2 3 5 8}\\  
\end{frame}

\begin{frame}[fragile]
\frametitle{\typ{range()}}
\kwrd{range([start,] stop[, step])}\\
\begin{itemize}
  \item \alert {range() returns a list of integers}
  \item \alert {The start and the step arguments are optional}  
\end{itemize}
\end{frame}

\begin{frame}[fragile]
  \frametitle{\typ{for} \ldots \typ{range()}}
Example: print squares of first \typ{n} numbers
  \begin{lstlisting}
In []: for i in range(5):
 ....:     print i, i * i
 ....:     
 ....:     
0 0
1 1
2 4
3 9
4 16
\end{lstlisting}
\inctime{15}
\end{frame}

\section{Lists}
\begin{frame}[fragile]
\frametitle{More List methods}
\begin{lstlisting}
In []: lst = [1,2,3,4,5,6,7,8]
In []: lst.reverse()
In []: lst
Out[]: [8, 7, 6, 5, 4, 3, 2, 1]

In []: lst.extend([0, -1, -2])
In []: lst
Out[]: [8, 7, 6, 5, 4, 3, 2, 1, 0, -1]

In []: lst.remove(0)
In []: lst
Out[]: [8, 7, 6, 5, 4, 3, 2, 1, -1]
\end{lstlisting}
\end{frame}

\begin{frame}[fragile]
\frametitle{List containership}
\begin{lstlisting}
In []: a = 8

In []: a in lst
Out[]: True

In []: b = 10
In []: b in lst
Out[]: False

In []: b not in lst
Out[]: True
\end{lstlisting}
\inctime{10}
\end{frame}

\section{Tuples}
\begin{frame}[fragile]
\frametitle{Tuples: Immutable lists}
\begin{lstlisting}
In []: tup = (1,2,3,4,5,6,7,8)
In []: tup[0]+tup[3]+tup[-1]
Out[]: 13
\end{lstlisting}
\begin{block}{Note:}
\begin{itemize}
\item Tuples are immutable - cannot be changed
\item Multiple return values in a function are actually tuples
\item Tuples are working behind the scenes in exchanging values - Tuple Unpacking
\end{itemize}
\end{block}
\inctime{5}
\end{frame}

\section{Dictionaries}
\begin{frame}[fragile]
\frametitle{Dictionary: Recall}
  \alert {lists and tuples: integer indexes :: dictionaries: string indexes}
\begin{lstlisting}
In []: player = {'Mat': 134,'Inn': 233, 
           'Runs': 10823, 'Avg': 52.53}

In []: player['Avg']
Out[]: 52.530000000000001
\end{lstlisting}
\begin{itemize}
\item Duplicate keys are not allowed!
\item Dictionaries are iterable through keys.
\end{itemize}
\end{frame}

\end{document}