Python Programming Tutorial

Introduction

• Learn Python programming for data science, machine learning, or web development.
• No prior knowledge needed; everything taught from scratch.
• Instructor: Mosh Hamadani.
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Uses of Python

• Multi-purpose programming language.
• Machine Learning and AI: Python is the top choice for projects.
• Web Development: Popular frameworks include Django.
  • Examples of websites built with Python/Django: YouTube, Instagram, Spotify, Dropbox, Pinterest.
• Automation: Automate repetitive tasks to save time and increase productivity.

Setting Up Python

1. Download Python from python.org:
   • Go to Downloads and select the latest version.
   • Check "Add Python to PATH" during installation (Windows).
2. Install a code editor:
   • Recommended: PyCharm (Community Edition is free).
   • Visit jetbrains.com/pycharm to download.
3. Create a new project in PyCharm:
   • Specify location and name (e.g., hello_world).
   • Create a new Python file (e.g., app.py).

Writing Your First Python Code

• Print Function: print("Hello World")
  • Strings are sequences of characters, surrounded by quotes.
• Run the code via the Run menu or shortcut (Ctrl+Shift+R on Mac).

Variables in Python

• Variables store temporary data: e.g., age = 20
• To print variable values, avoid quotes: print(age).
• Variables can be updated: age = 30

Types of Variables

• Integer: Whole numbers (e.g., age = 20).
• Float: Numbers with decimals (e.g., price = 19.95).
• String: Textual data (e.g., first_name = "Mosh").
• Boolean: True/False values (e.g., is_online = True).
• Python is case-sensitive.

User Input

• Use the input() function for user input:
  • Example: name = input("What is your name? ")
• String concatenation: print("Hello " + name).

Type Conversion

• Convert strings to integers with int(), floats with float(), and vice versa with str().
• Example of calculating age from birth year:

  birth_year = int(input("Enter your birth year: "))
  age = 2020 - birth_year
  print(age)
  

Arithmetic Operators

• Basic operations: + (addition), - (subtraction), * (multiplication), / (division).
• Division Types:
  • Single Slash / for float results.
  • Double Slash // for integer results.
• Modulus %: gives remainder.
• Exponent **: raises to power.

Comparison Operators

• Used to compare values: >, <, >=, <=, ==, !=.

Logical Operators

• Combine conditions: and, or, not.

If Statements

• Make decisions based on conditions:

  if temperature > 30:
      print("It's a hot day")
  elif temperature > 20:
      print("It's a nice day")
  else:
      print("It's cold")
  

Loops

• While Loops: Repeat code until condition fails.

  i = 1
  while i <= 5:
      print(i)
      i += 1
  

• For Loops: Iterate over lists or ranges.

  for number in range(1, 6):
      print(number)
  

Lists

• Create lists with square brackets:

  names = ["John", "Bob", "Mosh"]
  

• Access elements by index (zero-based).
• Modify lists with methods like append(), insert(), remove(), and clear().

Tuples

• Similar to lists, but immutable (cannot change once created).
• Defined with parentheses.

Conclusion

• Python is versatile for automation, data analysis, web development, etc.
• For more comprehensive learning, consider a dedicated Python course.