Document

Report
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Learn IT 2014: Python
Basic programming
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Agenda
 Python, PyCharm CE
 Basic programming concepts
 Creating an executable file
 Where
to go from here
using Py2Exe
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Python
Python version 2.7.6 (an interpreter)
Py2Exe version 0.6.9 win32-py2.7.exe
PyCharm Community Edition (an IDE)
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Python
 Easy to learn
 High-level
 Available
(simple syntax)
scripting language
on PC, Mac, Unix and Linux systems
 Drawing shapes
 Create web
using Turtle Module
apps, games, or search engine (such as Google)
 Lists of applications developed in Python
https://wiki.python.org/moin/Applications
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Programming Basic Elements
 Comments
 Data Types,
 Functions
 Turtle
 Loops
Variables and Variables Declaration
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Comments
 Are
used to describe the meaning and purpose of your
source code or program
 Can be
 Are
thought of as notes for ourselves and others
ignored by compilers and interpreters
 Should
be included in all programs
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Comments
Types
Single
Multiline
Examples
# This is a single line comment.
# This is multiline comments
# comments line 2…
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Programming Basic Elements
 Comments
 Data Types,
 Functions
 Turtle
 Loops
Variables and Variables Declaration
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Data Types
 Common data types:
 String – letters, numbers, and
 name =
symbols
“Ros”
 Numbers – integer and float
a=1
# integer or int
 b = 3.5 # float
 Boolean – True or False
 x = True
 y = False
 List – array in other languages
 a_list = [1, 2, 3, 4, 5, 6, 7, 8, 9]
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Variables & Variables Declaration
 Used
to store value or a piece of data
 Declaring
variables:
 Should be something meaningful
 Can
start with alphabet, and underscore but not number
 Case sensitive, i.e., name is not the same as Name
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Examples
Data Types
Variable Declaration
String
my_str = “Ros”
Integer
my_int = 90
Float
my_float = 90.87
Boolean
my_bool = True
Explanations
my_str = variable;
“Ros” = string value (notes the use of
quotations)
True is a value (note the use of an
uppercase T and F)
my_bool2 = False
List
my_list = []
my_list = varialbe
[] = an empty list, which you can use
append to add to the list
my_list2 = [1, 2, 3]
[1, 2, 3] = a list with some values
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Comments and Variables Example
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Programming Basic Elements
 Comments
 Data Types,
 Functions
 Turtle
 Loops
Variables and Variables Declaration
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Function
 A building
block of code or a chunk of code
that can be reused
 To
define a function in Python, we used a keyword “def”
Example
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Function in Python
Language
Python
Defining a function
def drawline():
# your code here
# your code here
drawline()
Explanations
colon (:) tells Python that a block of code is
coming next
block of code
(recommended 4 spaces indentation)
calling drawline() function
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Programming Basic Elements
 Comments
 Data Types,
 Functions
 Turtle
 Loops
Variables and Variables Declaration
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Turtle
 Turtle
(cursor) graphics is a Python graphic package for
creating vector graphics (scalable graphics)
 Turtle
 Three
graphics module is included in Python
things we need to know:
 Positions (distance)
 Directions (angle)
 States of the pens (line color, shape filled, line width,
etc.)
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Directions in Turtle
Facing Left
Facing Right
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Degrees in Turtle
0
45
315
270
90
225
135
180
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Turtle Commands
Commands
forward()
Descriptions
Moves the turtle forward
left()
Moves the turtle counter clockwise
right()
Moves the turtle clockwise
penup()
pendown()
color()
heading()
Picks up the turtles tail
Puts down the turtles tail
Changes the color of the turtle
(http://www.tcl.tk/man/tcl8.4/TkCmd/color
s.htm)
Returns the current heading
shape()
Shape of the turtle, can be arrow, classic,
turtle, or circle
done()
End turtle module
Visit https://docs.python.org/2/library/turtle.html for more information.
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Drawing Square
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Output
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Activity

Draw other shapes like triangle, rectangle, etc.

Formula
Shape
Sides
Range()
Angle
Triangle
3
3
360/3 = 120
Square/Rectangle
4
4
360/4 = 90
Octagon
8
8
360/8 = 45
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Programming Basic Elements
 Comments
 Data Types,
 Functions
 Turtle
 Loops
Variables and Variables Declaration
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Loops
 Looping
means repeating the same thing over and over
again.
 Two kinds of
loops:
 For loop – repeat a certain number of times
 While
loop – repeat until a certain thing happens (or as
long as some condition is met)
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For Loop
Examples
For loop
Outputs
1
for i in [1,2,3,4]:
print i
1
2
3
4
2
for i in [0,1,2]:
print “Hi”
Hi
Hi
HI
Explanations:
• The variable i (loop index; loop counter)
• The sequences in example started with the value 0 or 1 (example 1
and 2) and ended with any numbers (in example 1 and 2 the numbers
were 4 and 2 respectively)
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For Loop
 Range(start, stop, step) function
is a short cut for
entering starting and ending numbers
 range() function returns the
numbers between the start
and stop
 step in
 An
range() function is optional argument
argument is a value that we put inside the
parentheses and pass it to the function
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For Loop
Examples
Outputs
1
for i in range (1, 4):
print “Hello world”
Hello world
Hello world
Hello world
2
for i in range(2):
print “Learn IT 2014!”
Learn IT 2014
Learn IT 2014
Explanations:
• range(1, 4) means our program will print out the words “Hello world” 3 times
starting from 1 and ending before 4, which is 3. Note, step is optional. In this
case we didn’t specify step so it will count by 1
• If you want to print out 5 Hello world, how would you do that using
range(n1, n2)?
• Example 2 showed another way of specifying a number of loops you want
using just range(n)
• range(2) in example 2 is the same thing as range(0, 1)
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For Loop
Examples
for i in range (start, stop, step):
Outputs
1. Counting by 2
for i in range(1, 10, 2):
print "i =", i
i =1
i=3
i=5
i=7
i=9
2. Counting by 5
for i in range(1, 10, 5):
print "i =", i
i=1
i=6
3. Counting backward
for i in range(5, 0, -1):
print "i =", i
i=5
i=4
i=3
i=2
i=1
Using “step” examples
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For Loop
 We
can also use a for loop to count something else
other than numbers
Example
for i in [item, item, item, so on]:
for i in [“coffee”, “hot chocolate”, “tea”]:
print “I like to drink ” + i + “.”
Outputs
I like to drink coffee.
I like to drink hot chocolate.
I like to drink tea.
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While Loop

While loop is used to repeat a block of codes an unknown number
of times until a specific condition is met (conditional loop)

While loop is similar to if-else condition
Lines While loop
1
2
3
4
5
6
7
8
Explanations
temperature = 115
# set initial condition
while temperature > 112:
# first while loop
115 > 112
print temperature
Print 115
temperature = temperature – 1
115 – 1 = 114, loop back
until 112 > 112, which is
false
print “The tea is cool enough.”
Print “The tea is cool
enough.”
What happen if you leave out line 4?
(Code from http://anh.cs.luc.edu/python/hands-on/3.1/handsonHtml/whilestatements.html)
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Activity

Draw a square using a for loop

Formula
Shape
Sides
Range()
Angle
Triangle
3
3
360/3 = 120
Square/Rectangle
4
4
360/4 = 90
Octagon
8
8
360/8 = 45
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Square Code
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Py2Exe
Creating an executable file or standalone file using python
script
Py2exe,
http://www.logix4u.net/component/content/article/27tutorials/44-how-to-create-windows-executable-exe-frompython-script
Mac user,
http://pythonhosted.org/py2app
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Py2Exe

Create setup.py in the same folder where you want your python
script to be executable
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Example:
#setup.py
from distutils.core import setup
import py2exe
setup(console=[‘yourpythonfile.py'])
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Creating an EXE File

Go to Start and type “cmd” and press enter to open a command prompt
Note: Visit, http://www.pythoncentral.io/py2exe-python-to-exe-introduction/ for
more information
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Creating an EXE File
Navigate to the folder that we want to create a python file into an executable file
Example:
1. Create a directory called, “LearnIT2014” under C drive and copy the python file you
want to create an executable file to that directory
2. In the command prompt window, type the following command to change the directory
to LearnIT2014
c:\Users\n10rxa1> cd\
c:\>
c:\>cd LearnIT2014
3. This will take you to c:\LearnIT2014
4. Type the following command after c:\LearnIT2014>
c:\LearnIT2014>setup.py py2exe
5. When it is done creating, you will see two subfolders called “build” and “dist” created
under LearnIT2014
6. Double click “dist” folder to open, you should see an exe file
7. The “dist” folder is the folder that you can pack and send it your friends and family
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Where to go from here
 Python books: lists
of free books about
Pythonhttp://pythonbooks.revolunet.com/
 Hello
World Book
http://www.manning.com/sande2/
 How
to think like a computer scientist
http://www.openbookproject.net/thinkcs/python/english2e/
 Python for
Kids
http://www.nostarch.com/pythonforkids
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Where to go from here
 CodeAcademy: Python 2
http://www.codecademy.com/tracks/python
 GrokLearning: Python 3
https://groklearning.com/csedweek/
 Mobile
app using Python
http://kivy.org/
 Udemy (free
 Develop
Python on iPad)
games with Python https://www.udemy.com/gamedevelopment-fundamentals-with-python/
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Happy Coding

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