# HG changeset patch
# User Anoop Jacob Thomas<anoop@fossee.in>
# Date 1289395691 -19800
# Node ID 0c8ab2b5225b9d64abdf4f3caf1ec3a71571b21d
# Parent  1aa91f8d8d59c0a859c6bbc15aa0898e20815b4f
added slides for getting started with functions.

diff -r 1aa91f8d8d59 -r 0c8ab2b5225b getting-started-with-functions/slides.org
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/getting-started-with-functions/slides.org	Wed Nov 10 18:58:11 2010 +0530
@@ -0,0 +1,289 @@
+#+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:  Getting started with functions
+#+AUTHOR:  FOSSEE
+#+EMAIL:   info@fossee.in
+#+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.
+
+
+* Outline
+  - Define functions
+  - Pass arguments to functions
+  - Learn about docstrings
+  - Return values from functions
+
+* Function
+  - Eliminate code redundancy
+  - Help in code reuse
+  - Subroutine
+    - relatively independent of remaining code
+
+* ~f(x)~ a mathematical function
+
+  $f(x) = x^{2}$
+
+  : f(1) -> 1
+  : f(2) -> 4
+
+* Define ~f(x)~ in Python
+  #+begin_src python
+    def f(x):
+        return x*x
+  #+end_src
+
+  - ~def~ - keyword
+  - ~f~ - function name
+  - ~x~ - parameter / argument to function ~f~
+
+* Exercise 1
+
+  Write a python function named ~cube~ which computes the cube of a given
+  number ~n~.
+  
+  - Pause here and try to solve the problem yourself.
+
+* Solution
+  #+begin_src python
+    def cube(n):
+    	return n**3
+  #+end_src
+
+* ~greet~ function
+
+ Function ~greet~ which will print ~Hello World!~.
+ #+begin_src python
+    def greet():
+    	print "Hello World!"
+ #+end_src
+  - Call the function ~greet~
+    : In []: greet()
+    : Hello World!
+
+* Exercise 2
+
+  Write a python function named ~avg~ which computes the average of
+  ~a~ and ~b~.
+
+  - Pause here and try to solve the problem yourself.
+
+* Solution 2
+ #+begin_src python
+    def avg(a,b):
+    	return (a + b)/2
+ #+end_src
+
+ - ~a~ and ~b~ are parameters
+ - ~def f(p1, p2, p3, ... , pn)~
+
+* Docstring
+
+  - Documenting/commenting code is a good practice
+   #+begin_src python
+     def avg(a,b):
+         """ avg takes two numbers as input 
+	 (a & b), and returns the average 
+	 of a and b"""
+	 return (a+b)/2
+   #+end_src
+  - Docstring
+    - written in the line after the ~def~ line.
+    - Inside triple quote.
+  - Documentation
+    : avg?
+* Exercise 3
+  Add docstring to the function f.
+
+* Solution 3
+
+#+begin_src python
+  def f(x):
+      """Accepts a number x as argument and,
+      returns the square of the number x."""
+      return x*x
+#+end_src
+
+* Exercise 4
+  Write a python function named ~circle~ which returns the area and
+  perimeter of a circle given radius ~r~.
+
+* Solution 4
+#+begin_src python
+  def circle(r):
+      """returns area and perimeter of a circle given 
+      radius r"""
+      pi = 3.14
+      area = pi * r * r
+      perimeter = 2 * pi * r
+      return area, perimeter
+#+end_src
+
+* ~what~
+#+begin_src python
+
+ def what( n ):
+     if n < 0: n = -n
+     while n > 0:
+         if n % 2 == 1:
+             return False
+         n /= 10
+     return True
+#+end_src
+
+* ~even_digits~
+#+begin_src python
+ def even_digits( n ):
+    """returns True if all the digits of number 
+    n is even returns False if all the digits 
+    of number n is not even"""
+     if n < 0: n = -n
+     while n > 0:
+         if n % 2 == 1:
+             return False
+         n /= 10
+     return True
+#+end_src
+
+* ~what~
+#+begin_src python
+ def what( n ):
+     i = 1
+     while i * i < n:
+         i += 1
+     return i * i == n, i
+#+end_src
+
+* ~is_perfect_square~
+#+begin_src python
+ def is_perfect_square( n ):
+     """returns True and square root of n, 
+     if n is a perfect square, otherwise 
+     returns False and the square root 
+     of the next perfect square"""
+     i = 1
+     while i * i < n:
+         i += 1
+     return i * i == n, i
+#+end_src
+
+* Summary
+ - Functions in Python
+ - Passing parameters to a function
+ - Returning values from a function
+
+ - We also did few code reading exercises.
+
+* 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 -r 1aa91f8d8d59 -r 0c8ab2b5225b getting-started-with-functions/slides.tex
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/getting-started-with-functions/slides.tex	Wed Nov 10 18:58:11 2010 +0530
@@ -0,0 +1,323 @@
+% Created 2010-11-10 Wed 18:55
+\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 functions}
+\author{FOSSEE}
+\date{}
+
+\usetheme{Warsaw}\usecolortheme{default}\useoutertheme{infolines}\setbeamercovered{transparent}
+\begin{document}
+
+\maketitle
+
+
+
+
+
+
+
+
+
+    
+    
+
+
+
+\begin{frame}
+\frametitle{Outline}
+\label{sec-1}
+
+\begin{itemize}
+\item Define functions
+\item Pass arguments to functions
+\item Learn about docstrings
+\item Return values from functions
+\end{itemize}
+\end{frame}
+\begin{frame}
+\frametitle{Function}
+\label{sec-2}
+
+\begin{itemize}
+\item Eliminate code redundancy
+\item Help in code reuse
+\item Subroutine
+
+\begin{itemize}
+\item relatively independent of remaining code
+\end{itemize}
+
+\end{itemize}
+\end{frame}
+\begin{frame}[fragile]
+\frametitle{\texttt{f(x)} a mathematical function}
+\label{sec-3}
+
+
+  $f(x) = x^{2}$
+
+\begin{verbatim}
+   f(1) -> 1
+   f(2) -> 4
+\end{verbatim}
+\end{frame}
+\begin{frame}[fragile]
+\frametitle{Define \texttt{f(x)} in Python}
+\label{sec-4}
+
+\begin{verbatim}
+def f(x):
+    return x*x
+\end{verbatim}
+
+\begin{itemize}
+\item \texttt{def} - keyword
+\item \texttt{f} - function name
+\item \texttt{x} - parameter / argument to function \texttt{f}
+\end{itemize}
+\end{frame}
+\begin{frame}
+\frametitle{Exercise 1}
+\label{sec-5}
+
+
+  Write a python function named \texttt{cube} which computes the cube of a given
+  number \texttt{n}.
+  
+\begin{itemize}
+\item Pause here and try to solve the problem yourself.
+\end{itemize}
+\end{frame}
+\begin{frame}[fragile]
+\frametitle{Solution}
+\label{sec-6}
+
+\begin{verbatim}
+def cube(n):
+    return n**3
+\end{verbatim}
+\end{frame}
+\begin{frame}[fragile]
+\frametitle{\texttt{greet} function}
+\label{sec-7}
+
+
+ Function \texttt{greet} which will print \texttt{Hello World!}.
+\begin{verbatim}
+def greet():
+    print "Hello World!"
+\end{verbatim}
+\begin{itemize}
+\item Call the function \texttt{greet}
+\begin{verbatim}
+     In []: greet()
+     Hello World!
+\end{verbatim}
+
+\end{itemize}
+\end{frame}
+\begin{frame}
+\frametitle{Exercise 2}
+\label{sec-8}
+
+
+  Write a python function named \texttt{avg} which computes the average of
+  \texttt{a} and \texttt{b}.
+
+\begin{itemize}
+\item Pause here and try to solve the problem yourself.
+\end{itemize}
+\end{frame}
+\begin{frame}[fragile]
+\frametitle{Solution 2}
+\label{sec-9}
+
+\begin{verbatim}
+def avg(a,b):
+    return (a + b)/2
+\end{verbatim}
+
+\begin{itemize}
+\item \texttt{a} and \texttt{b} are parameters
+\item \texttt{def f(p1, p2, p3, ... , pn)}
+\end{itemize}
+\end{frame}
+\begin{frame}[fragile]
+\frametitle{Docstring}
+\label{sec-10}
+
+
+\begin{itemize}
+\item Documenting/commenting code is a good practice
+\begin{verbatim}
+def avg(a,b):
+    """ avg takes two numbers as input 
+    (a & b), and returns the average 
+    of a and b"""
+    return (a+b)/2
+\end{verbatim}
+\item Docstring
+
+\begin{itemize}
+\item written in the line after the \texttt{def} line.
+\item Inside triple quote.
+\end{itemize}
+
+\item Documentation
+\begin{verbatim}
+     avg?
+\end{verbatim}
+
+\end{itemize}
+\end{frame}
+\begin{frame}
+\frametitle{Exercise 3}
+\label{sec-11}
+
+  Add docstring to the function f.
+\end{frame}
+\begin{frame}[fragile]
+\frametitle{Solution 3}
+\label{sec-12}
+
+
+\begin{verbatim}
+def f(x):
+    """Accepts a number x as argument and,
+    returns the square of the number x."""
+    return x*x
+\end{verbatim}
+\end{frame}
+\begin{frame}
+\frametitle{Exercise 4}
+\label{sec-13}
+
+  Write a python function named \texttt{circle} which returns the area and
+  perimeter of a circle given radius \texttt{r}.
+\end{frame}
+\begin{frame}[fragile]
+\frametitle{Solution 4}
+\label{sec-14}
+
+\begin{verbatim}
+def circle(r):
+    """returns area and perimeter of a circle given 
+    radius r"""
+    pi = 3.14
+    area = pi * r * r
+    perimeter = 2 * pi * r
+    return area, perimeter
+\end{verbatim}
+\end{frame}
+\begin{frame}[fragile]
+\frametitle{\texttt{what}}
+\label{sec-15}
+
+\begin{verbatim}
+
+def what( n ):
+    if n < 0: n = -n
+    while n > 0:
+        if n % 2 == 1:
+            return False
+        n /= 10
+    return True
+\end{verbatim}
+\end{frame}
+\begin{frame}[fragile]
+\frametitle{\texttt{even\_digits}}
+\label{sec-16}
+
+\begin{verbatim}
+def even_digits( n ):
+   """returns True if all the digits of number 
+   n is even returns False if all the digits 
+   of number n is not even"""
+    if n < 0: n = -n
+    while n > 0:
+        if n % 2 == 1:
+            return False
+        n /= 10
+    return True
+\end{verbatim}
+\end{frame}
+\begin{frame}[fragile]
+\frametitle{\texttt{what}}
+\label{sec-17}
+
+\begin{verbatim}
+def what( n ):
+    i = 1
+    while i * i < n:
+        i += 1
+    return i * i == n, i
+\end{verbatim}
+\end{frame}
+\begin{frame}[fragile]
+\frametitle{\texttt{is\_perfect\_square}}
+\label{sec-18}
+
+\begin{verbatim}
+def is_perfect_square( n ):
+    """returns True and square root of n, 
+    if n is a perfect square, otherwise 
+    returns False and the square root 
+    of the next perfect square"""
+    i = 1
+    while i * i < n:
+        i += 1
+    return i * i == n, i
+\end{verbatim}
+\end{frame}
+\begin{frame}
+\frametitle{Summary}
+\label{sec-19}
+
+\begin{itemize}
+\item Functions in Python
+\item Passing parameters to a function
+\item Returning values from a function
+\item We also did few code reading exercises.
+\end{itemize}
+\end{frame}
+\begin{frame}
+\frametitle{Thank you!}
+\label{sec-20}
+
+  \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}