Session 0 Python Programming slide series is part of Object-Oriented System Analysing & Designing in CS.QIAU Undergrad.

1. CS.QIAU - Winter 2020
PYTHONIntroduction - Session 0
Omid AmirGhiasvand
Programming

2. NATURALLANGUAGEConstructed communication tool to convoy meaning

3. Formal language engineered to communicate instructions to computer
PROGRAMMING LANGUAGE

4. Programs and Programming Languages
▸ Programs are created using programming languages to control
behaviors and output of a computer through accurate algorithms.
▸ Programming Languages
▸ Machine Language.
▸ Assembly Language.
▸ High-Level Language - More like human language.
▸ Python
▸ Java
▸ GoLang
▸ C++
step by step instruction
to solve a problem

5. Data Program Result
TRADITIONAL APPROACH TO SOLVE PROBLEM
Program implements an algorithm which is in fact a list of rules

6. A machine-learning system is trained rather than explicitly
programmed. It’s presented with many examples relevant to a task,
and it finds statistical structure in these examples that eventually
allows the system to come up with rules for automating the task.
NEW APPROACH TO SOLVE PROBLEM
MACHINE LEARNING

7. Data
ML System Model
Label
Model is an algorithm which is trained by Machine Learning System to solve problem

8. Program Lifecycle - C++
▸ Editing the Code - Using text editor or IDE
▸ PreProcessing
▸ Compile
▸ Link
▸ Load
▸ Execute
Depend on runtime system and
execution model of the language

9. Python Program Lifecycle
▸ Behind the scene
.py Python
Compiler
.pyc Python VM
Interpreter
Python byte-codes loaded into Python Runtime
and interpreted by Python Virtual Machine
Byte-code is lower level and
p l a t f o r m i n d e p e n d e n t
presentation of your source code

10. Building Block of Programming Language
▸ Sequence
▸ The code will run by computer in order - from top to bottom
▸ Decision or Selection - If
▸ The execution of some code only when some condition is true.
▸ Loop or Iteration - For/While
▸ The execution of some code while some condition is true.

11. Setting Up Your Programming Environment
▸ Python Versions
▸ Python 2 or 3
▸ IDE
▸ PyCharm: A full-fledged IDE
▸ Atom/Sublime and …
▸ Visual Studio Code
▸ You can use any text editor that you like and save your program
with .py extension.
We use -> Python 3.8 and PyCharm 2020
myCode.py

12. Setup Development Environment
▸ Install Python Interpreter for your Platform (Windows/Mac/Linux)
▸ www.python.org
▸ Add python to your system PATH environment variable
▸ An environment variable is a dynamic named value that can affect the way
running process will behave on a computer.
▸ Install PyCharm
▸ Community
▸ Professional
You can also set PYTHONHOME

14. Test Development Environment
▸ Open Terminal (CMD in Windows or Terminal in Linux/MAC OS)
▸ python3 - - version
Python
Version

15. Hello World Project
▸ Open PyCharm.
▸ Create New Project.
▸ Select Pure Python.
▸ Set Location and Name.
▸ Example: CS.QIAU-Python.
▸ Right-Click in Project Folder and Select “New” and Select “Python File”
▸ Set file name.
▸ Example: main.py
▸ Write Code in main.py
▸ Run the Code and Check the output.

16. Select

17. Project
Name
Virtual
Environment

18. Project
Folder

25. Project
Name and
Folder
main.py in
project root
Code Editor
Windows
main.py
Output
Python
Code
Run
Windows

26. Break Down the Hello World Program - Simpler Version
▸ Comments - line 1..6
▸ Define main() method - line 9
▸ create welcome_message variable - line 10
▸ call print() method - line 11..13
▸ Check special variable __name__ ==“__main__”
▸ This line of code is the entry point to your program.
▸ Call main() method - line 17
2 underscores

27. Comments
main()
function
definition
define
and initialize
a string
variable
Print *
print
welcome_message
value
Call
main()
function
Check value of
special variable
__name__

28. “The Unexamined Life Is Not Worth Living”