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#+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
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* 
#+begin_latex
\begin{center}
\vspace{12pt}
\textcolor{blue}{\huge Writing python scripts}
\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, 

  - Understand what is importing.
  - Write your own Python modules.
  - Understand the \_\_name\_\_==``\_\_main\_\_" idiom
* Pre-requisite
Spoken tutorial on -
- Using Python modules
* GCD
#+begin_src Python
def gcd(a, b):

    while b:
        a, b = b, a%b

    return a
    if gcd(40, 12) == 4:
        print "Everything OK"
    else:
        print "The GCD function is wrong"
#+end_src
* \_\_name\_\_ variable
#+begin_src Python
if __name__ == "__main__":
#+end_src
* Summary
In this tutorial, we have learnt to,

 - Know what happens when we import a module.
 - Use a script as a module.
 - Write test functions using the ``\_\_name\_\_'' idiom. 
* Evaluation
1. Which of the following variables contains the locations to search for
   python modules
   
   - sys.pythonpath
   - sys.path
   - os.pythonpath
   - os.path

2. A module should contain only functions.
   - True 
   - False

* Evaluation contd..
- The script ``utils.py`` is in one of locations of PYTHONPATH and contains
    the following code
#+begin_src Python
def show(x):
    print x

show("Hello World")

if __name__ == "__main__":

    show("Hello Test")
#+end_src
  How do you use the ``show`` function after doing ``import utils``

   - utils.show("hey")
   - show("hey")
   - utils.py.show("hey")
   - utils.py.show.py("hey")
* Solutions
1. sys.path

2. False

3. utils.show("hey")
* 
#+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