Update the project

Author: braboj

README.md

@@ -11,22 +11,35 @@ SOLID principles, design patterns, and best practices.
 
 Ensure that the following tools are installed before setting up the project:
 
+- **IDE of your choice** - PyCharm, Visual Studio Code, or any other Python IDE
 - **Python 3.10+** - the examples rely on modern Python features
 - **git** - to clone this repository
 
 ## Installation
 
+Clone the repository to your local machine:
+
+```bash
+git clone https://github.com/braboj/python-by-example.git
+```
+
+Change into the project directory:
+
+```bash
+cd python-by-example
+```
+
 Create a virtual environment and install dependencies:
 
-#### Linux/macOS
+- For Linx and macOS, use the following commands:
 
 ```bash
 python -m venv .venv
 source .venv/bin/activate
 pip install -r requirements.txt
 ```
 
-#### Windows
+- For Windows, use the following commands:
 
 ```cmd
 python -m venv .venv
@@ -36,13 +49,28 @@ pip install -r requirements.txt
 
 ## Usage
 
-Run the examples using Python:
+The examples are intented to be used with an IDE of your choice so that you can
+run, debug, and modify them as needed. Just open the project in your IDE, and 
+you can start exploring the examples.
+
+```text
+.python-by-example
+├── .venv/                  # Virtual environment directory
+├── examples/               # Directory containing all the examples
+│   ├── A01_introduction/   # Introduction examples
+│   │   ├── hello_world.py
+```
+
+You can also run the examples from the command line. For example, to run the 
+`hello_world.py` example, use the following command:
 
 ```bash
-python path/to/example.py
+python examples/A01_introduction/hello_world.py
 ```
 
 
 ## License
 
-This project is proprietary software. Copying or distribution is prohibited without express permission from the author.
+This project is proprietary software. Copying or distribution is prohibited 
+without express permission from the author. See the [LICENSE](LICENSE) file for
+more details.

examples/A02_variables/07_list_data.py

@@ -12,37 +12,32 @@
 # - Mutable: Can be modified after creation
 # - Ordered: Order of elements is preserved
 # - Heterogeneous: Can contain elements of different types
+# - Passed by reference: Changes to one variable affect all references
 
-# Indexed
+# Indexed (elements can be accessed by their index)
 a = [1, 2, 3]
 print(a[0])
 # Output: 1
 
-# Mutable
+# Mutable (can be modified after creation)
 b = [1, 2, 3]
 b[0] = 4
 print(b)
 # Output: [4, 2, 3]
 
-# Ordered
+# Ordered (order of elements is preserved)
 c = [2, 1, 3]
 print(c)
 # Output: [2, 1, 3]
 
-# Heterogeneous
+# Heterogeneous (can contain elements of different types)
 d = [1, 'two', 3.0]
 print(d)
 # Output: [1, 'two', 3.0]
 
-# (!) Passing by reference (!)
+# Passed by reference (changes to one variable affect all references)
 l1 = [1, 2, 3]
 l2 = l1
 l2[0] = 4
 print(l1, l2)
-# Output: [4, 2, 3]
-
-# Copying a list
-l3 = l1.copy()
-l3[0] = 5
-print(l1, l3)
-# Output: [4, 2, 3] [5, 2, 3]
+# Output: [4, 2, 3] [4, 2, 3]

examples/A02_variables/08_tuple_data.py

@@ -5,15 +5,20 @@
 # and performance benefits they provide over lists, especially when dealing
 # with large datasets. They also can be used as keys in dictionaries.
 #
-# - Immutable: Once created, the string cannot be changed.
-# - Ordered: The characters in the string maintain their order.
-# - Indexed: Each character in the string can be accessed by its index.
-# - Heterogeneous: Strings can contain characters of different types
+# - Immutable: Once created, the tuple cannot be changed.
+# - Ordered: The elements in the tuple maintain their order.
+# - Indexed: Each element in the tuple can be accessed by its index.
+# - Heterogeneous: Tuples can contain characters of different types
 
 # Immutable (a change creates a new object)
 tuple1 = (1, 2, 3)
-tuple2 = tuple1 + (4, 5)
-print(id(tuple1), id(tuple2))
+tuple2 = tuple1
+print(tuple2 is tuple1)     # Check if both variables point to the same object
+tuple2 += (4, 5)
+print(tuple2 is tuple1)     # After modification, they are different objects
+# Output:
+# False
+# True
 
 # Ordered (characters maintain their order)
 tuple3 = (1, 2, 3)

examples/A02_variables/09_set_data.py

@@ -5,6 +5,7 @@
 # union, intersection, and difference. The set type has the following
 # characteristics:
 #
+# - Passed by reference: Changes to one variable affect all references
 # - Unique: A set cannot contain duplicate elements.
 # - Mutable: You can add or remove elements from a set.
 # - Unordered: The elements in a set do not have a specific order.
@@ -18,11 +19,6 @@
 print(s1, s2)
 # Output: {1, 2, 3, 4} {1, 2, 3, 4}
 
-# Copying a set
-s3 = s1.copy()
-s3.add(5)
-print(s1, s3)
-
 # All elements are unique
 a = {1, 1, 2, 2, 3, 3}
 print(id(a), a, sep=": ")

examples/A02_variables/10_dictionary_data.py

@@ -5,12 +5,20 @@
 # appears more than once, the last assigned value is retained. The
 # dictionary variable has the following properties:
 #
+# - Passed by reference: Changes to one variable affect all references
 # - Key access: You can access values using their keys
 # - Unique keys: Each key must be unique within the dictionary
 # - Mutable: Can be modified after creation
 # - Ordered: The order of inserted items is maintained (as of Python 3.7)
 # - Heterogeneous: Can contain keys and values of different types
 
+# Passed by reference (changes to one variable affect all references)
+d1 = {'junior': 1, 'mid': 2, 'senior': 3}
+d2 = d1
+d2['junior'] = 4
+print(d1, d2)
+# Output: {'junior': 4, 'mid': 2, 'senior': 3} {'junior': 4, 'mid': 2, 'senior': 3}
+
 # Key access
 a = {'junior': 1, 'mid': 2, 'senior': 3}
 print(a['mid'])

examples/A02_variables/11_string_data.py

@@ -12,7 +12,8 @@
 # Immutable (a change creates a new object)
 string1 = "Hello, world!"
 string2 = string1.replace("world", "Python")
-print(id(string1), id(string2))
+print(string2 is string1)
+# Output: False
 
 # Ordered (characters maintain their order)
 string3 = "Python"