Merge pull request #88 from codewithdhruba01/add/Python-Syntax

docs: Created full tutorial on Python Variables including scope, memory, and dynamic typing

Author: sanjay-kv

docs/python/_category_.json

@@ -1,6 +1,6 @@
 {
   "label": "Python",
-  "position": 3,
+  "position": 4,
   "link": {
     "type": "generated-index",
     "description": "Python is a high-level, interpreted programming language known for its clean syntax and code readability. It supports multiple programming paradigms including procedural, object-oriented, and functional programming. Python is widely used in web development, data science, machine learning, automation, and scripting. Its simplicity and versatility make it one of the most popular languages for beginners and professionals alike."

docs/python/assets/data-type.png

@@ -0,0 +1,240 @@
+---
+id: python-variables
+title: Python Variables
+sidebar_label: Python Variables #displays in sidebar
+sidebar_position: 3
+tags:
+  [
+    Python,
+    Introduction of python,
+    Python Syntax,
+    Python Variables,
+
+  ]
+
+---
+
+# Python Variables
+
+In Python, variables are used to store data that can be referenced and manipulated during program execution. A variable is essentially a name that is assigned to a value. Unlike many other programming languages, Python variables do not require explicit declaration of type. The type of the variable is inferred based on the value assigned.
+
+Variables act as placeholders for data. They allow us to store and reuse values in our program.
+
+
+### 1. What is a Variable?
+
+A variable is like a container for storing data values. You don’t need to declare its type explicitly — Python handles it dynamically.
+
+```python
+x = 5
+y = "Hello"
+````
+
+Here:
+
+* `x` is of type `int`
+* `y` is of type `str`
+
+
+
+### 2. How to Declare and Assign Variables
+
+You simply write a variable name, use the `=` sign, and assign a value.
+
+```python
+a = 10
+name = "GeeksForGeeks"
+price = 99.99
+is_active = True
+```
+
+Python automatically understands the type of variable.
+
+
+### 3. Multiple Assignments in One Line
+
+Python allows assigning values to multiple variables in a single line.
+
+```python
+x, y, z = 1, 2, 3
+```
+
+You can also assign the **same value to multiple variables**:
+
+```python
+a = b = c = 100
+```
+
+
+### 4. Variable Naming Rules
+
+* Must start with a letter (a–z, A–Z) or an underscore (\_)
+* Can contain letters, digits, and underscores
+* Are case-sensitive (`name` and `Name` are different)
+* Cannot use reserved keywords like `if`, `class`, `def`, etc.
+
+```python
+# Valid
+my_var = 1
+_var = 2
+var3 = 3
+
+# Invalid
+3var = 10       # starts with digit
+my-var = 20     # hyphen not allowed
+def = 30        # 'def' is a keyword
+```
+
+
+### 5. Standard Data Types in Python
+
+Python variables can hold different types of data:
+
+
+  <img src="./assets/data-type.png"/>
+
+### 6. Type Checking with `type()`
+
+```python
+x = 10
+print(type(x))   # <class 'int'>
+```
+
+
+
+### 7. Changing Variable Type Dynamically
+
+Python allows dynamic typing:
+
+```python
+x = 5
+print(type(x))  # <class 'int'>
+
+x = "Hello"
+print(type(x))  # <class 'str'>
+```
+
+
+### 8. Deleting a Variable with `del`
+
+You can remove a variable from memory using `del`.
+
+```python
+x = 100
+del x
+
+print(x)  # Raises NameError
+```
+
+
+### 9. Scope of Variables
+
+There are **two types of variable scope**:
+
+### 10. Global Variable
+
+Declared outside functions, accessible anywhere.
+
+```python
+x = "global"
+
+def show():
+    print(x)
+
+show()  # Output: global
+```
+
+### 11. Local Variable
+
+Declared inside functions and accessible only inside them.
+
+```python
+def greet():
+    msg = "Hello"
+    print(msg)
+
+greet()
+print(msg)  # Error: NameError
+```
+
+
+
+### 🟢 The `global` Keyword
+
+Use `global` to modify global variables inside a function.
+
+```python
+x = 10
+
+def update():
+    global x
+    x = 20
+
+update()
+print(x)  # Output: 20
+```
+
+
+### 12. Memory Management in Python
+
+* Python variables are **names** bound to **objects in memory**.
+* Use `id()` to get the memory address (or reference ID) of a variable.
+
+```python
+x = 5
+print(id(x))
+```
+
+If two variables have the same immutable value, they may share the same memory.
+
+```python
+a = 100
+b = 100
+print(id(a) == id(b))  # True
+```
+
+
+### 🟢 Example Program
+
+```python
+# Python Variable Example
+
+name = "Dhruba"
+age = 22
+price = 49.99
+is_valid = True
+items = ["pen", "notebook"]
+
+print("Name:", name)
+print("Age:", age)
+print("Price:", price)
+print("Valid:", is_valid)
+print("Items:", items)
+```
+
+**Output:**
+
+```
+Name: Dhruba
+Age: 22
+Price: 49.99
+Valid: True
+Items: ['pen', 'notebook']
+```
+
+
+## Summary
+
+* Python variables store different types of data without explicit declaration.
+* Variables are case-sensitive and follow naming rules.
+* Scope determines where a variable is accessible.
+* `global` and `del` are important keywords for variable handling.
+* Python handles memory management internally but allows inspection via `id()`.
+
+
+### Highlights
+
+* Covers both global and local variables
+* Explains `del`, `global`, and `id()` functions
+* Includes formatted tables and output blocks
+* Beginner-friendly explanation with examples