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#+LaTeX_CLASS: beamer
#+LaTeX_CLASS_OPTIONS: [presentation]
#+BEAMER_FRAME_LEVEL: 1
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#+LaTeX_CLASS: beamer
#+LaTeX_CLASS_OPTIONS: [presentation]
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#+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:
#+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
*
#+begin_latex
\begin{center}
\vspace{12pt}
\textcolor{blue}{\huge Getting started with \texttt{functions}}
\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,
- Define a function.
- Define functions with arguments.
- Learn about docstrings.
- Learn about function return value.
- Read and understand code.
* Pre-requisite
Spoken tutorial on -
- Conditionals.
- Loops.
* Function
- Eliminate code redundancy
- Help in code reuse
- Subroutine
- relatively independent of remaining code
* 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~.
* Exercise 2
- Write a python function named ~avg~ which computes the average of
~a~ and ~b~.
* 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~.
* ~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
In this tutorial, we have learnt to,
- Define functions in Python by using the keyword ``def''.
- Call the function by specifying the function name.
- Assign a docstring to a function by putting it as a triple quoted string.
- Pass parameters to a function.
- Return values from a function.
* Evaluation
1. What will the function do?
#+begin_src Python
def what(x)
return x*x
#+end_src
- Returns the square of x
- Returns x
- Function doesn't have docstring
- Error
2. How many arguments can be passed to a python function?
- None
- One
- Two
- Any
3. Write a function which calculates the area of a rectangle.
* Solutions
1. Error
2. Any
3.
#+begin_src Python
def area(l,b):
return l * b
#+end_src
*
#+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
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