Varibles in Python

Variables

In Python, variables are created when you assign a value to them
- Example: x = 5
Unlike some programming languages, Python has no command for declaring variables
Variable names must follow certain rules:
- Can contain letters, digits and underscores
  - Example: age, age_1, _age
- Must start with a letter or underscore
  - Example: valid_name, _name
  - Example (invalid): 1_name
- Are case-sensitive (age, Age and AGE are 3 different variables)
  - Example: myAge = 25, MyAge = 30
- Cannot start with a digit
  - Example (invalid): 1variable
- Can have a maximum length of 79 characters
- Cannot use reserved keywords as names
  - Example (invalid): True = 5

Python allows assigning a single value to a single variable
- Example: x = 5, name = "John"
You can assign a new value to an existing variable
- Example: x = 4, x = "hello"
You can assign multiple objects to multiple variables
- Example: a, b, c = 1, 2, "three"

Python interprets literals based on rules of data types
- Example: x = 1 # x is int
- Example: y = 1.5 # y is float
You can convert data types explicitly using type conversion functions:
- int() - Converts to integer
  - Example: x = int(1) # x is 1
  - Example: y = int(2.8) # y is 2
- float() - Converts to float
  - Example: x = float(1) # x is 1.0
- str() - Converts to string
  - Example: x = str(97) # x is '97'

Use the type() function to get the data type of a variable
- Example: print(type(x)), where x is an existing variable

Variable names are case-sensitive
- Example: VALUE and value are different variables
It's good practice to use descriptive variable names
- Example: student_age, user_email
Python style guides recommend:
- CamelCase for classes
  - Example: ComplexNumber
- under_scores for functions and variables(snake case)
  - Example: calculate_area, init, print_students