This guide will help you understand different variable types in Python using the Python interpreter environment. We'll explore int, bool, float, and str variables with practical examples.

To begin:

1. Open your terminal/command prompt
2. Type python3 (or python) and press Enter
3. You should see the Python prompt: >>>

Definition: An integer variable stores whole numbers without decimal points.

How to declare:

variable_name = value

TYPE into Python interpreter:

>>> age = 25
>>> age
25

>>> score = 100
>>> score
100

>>> negative = -10
>>> negative
-10

>>> sum_total = age + score
>>> sum_total
125

Type dir() to see all variables in your current namespace, or use globals() to see global variables.

Save the work in a file called vars.py.

# Exit Python interpreter with exit() or Ctrl-D
# Create a file vars.py with your variable examples

age = 25
score = 100
negative = -10
sum_total = age + score

print(f"Age: {age}")
print(f"Score: {score}")
print(f"Sum: {sum_total}")

Now, save the repo to your GitHub account.

git add .
git commit -m "Add Python Variables Guide"
git push

Go to a browser and navigate to your GitHub account to see the changes in this repository.

Okay go back to the terminal and let's continue.

Definition: A boolean variable stores True/False values.

How to declare:

variable_name = True/False

TYPE into Python interpreter:

>>> is_student = True
>>> is_student
True

>>> has_passed_exam = False
>>> has_passed_exam
False

>>> result = 10 > 5
>>> result
True

>>> is_equal = (15 == 15)
>>> is_equal
True

Definition: A float variable stores decimal numbers with precision.

How to declare:

variable_name = value

TYPE into Python interpreter:

>>> price = 19.99
>>> price
19.99

>>> temperature = -2.5
>>> temperature
-2.5

>>> result = 10.5 + 3.7
>>> result
14.2

>>> division = 10.0 / 3.0
>>> division
3.3333333333333335

Definition: A string variable stores text (sequence of characters).

How to declare:

variable_name = "text"
variable_name = 'text'

Hey, here, replace "John" with your name.

TYPE into Python interpreter:

>>> name = "John"
>>> name
'John'

>>> greeting = "Hello, World!"
>>> greeting
'Hello, World!'

>>> combined = name + " says " + greeting
>>> combined
'John says Hello, World!'

>>> empty = ""
>>> empty
''

>>> formatted = f"{name} says {greeting}"
>>> formatted
'John says Hello, World!'

Unlike Java, Python variables don't need type declarations. Python figures out the type automatically:

>>> x = 5          # x is an int
>>> type(x)
<class 'int'>

>>> x = "hello"    # now x is a string
>>> type(x)
<class 'str'>

>>> x = 3.14       # now x is a float
>>> type(x)
<class 'float'>

1. Try typing these examples in the Python interpreter
2. Experiment with different values
3. Try combining variables in operations
4. Use type(variable) to check the type of any variable
5. Use dir() or globals() to see all variables
6. Save your work in Python files (.py extension)
7. Use exit() to leave the Python interpreter

Be sure to do commit of all this work to your GitHub repository.

git add .
git commit -m "Add Python Variables Guide"
git push

• Dynamic typing: No need to declare variable types
• Snake_case: Python uses snake_case for variable names (not camelCase)
• f-strings: Use f"text {variable}" for string formatting
• Multiple assignment: x, y = 1, 2
• Type checking: Use type(variable) to check types

• Don't forget that Python is case-sensitive
• Remember that strings can use single or double quotes
• Python uses True/False (capitalized) not true/false
• Use snake_case for variable names in Python
• Remember that variables are dynamically typed

This guide should give you a solid foundation for understanding and working with basic Python variables in the interpreter. Practice with these examples and try creating your own variables to become more comfortable with these concepts.

Now go to the ClassPerson.md guide to learn about creating custom classes in Python.