Merge pull request #157 from codewithdhruba01/Dictionaries/Docusaurus

Add Python dictionaries documentation

Author: sanjay-kv

docs/python/python-dictionaries.md

@@ -0,0 +1,220 @@
+---
+id: python-dictionaries
+title: Python Dictionaries
+description: Complete theoretical explanation of dictionaries in Python, covering creation, modification, methods, and use-cases.
+sidebar_label: Python Dictionaries #displays in sidebar
+sidebar_position: 11
+tags:
+  [
+    Python,
+    Introduction of python,
+    List in Python,
+    Python Syntax,
+    Variables,
+    Operators,
+    Type Casting,
+    String,
+    Tuple in Python,
+    Python Dictionaries
+
+  ]
+
+---
+
+
+# Python Dictionaries
+
+A **dictionary** in Python is an unordered, mutable, and indexed collection of key-value pairs. It is one of the most powerful and flexible built-in data structures in Python, suitable for representing structured data.
+
+## What is a Dictionary?
+
+Dictionaries hold data in the form of key-value pairs. Each key is unique and maps to a specific value. Values can be of any data type, while keys must be immutable (like strings, numbers, or tuples).
+
+### Example:
+```python
+person = {
+    "name": "Alice",
+    "age": 25,
+    "city": "New York"
+}
+````
+
+## Properties of Dictionaries
+
+* Keys are unique.
+* Keys must be immutable.
+* Values can be of any data type.
+* Dictionaries are mutable and can be changed after creation.
+* In Python 3.7+, dictionaries maintain insertion order.
+
+## Creating Dictionaries
+
+### Using Curly Braces:
+
+```python
+data = {"a": 1, "b": 2}
+```
+
+### Using the `dict()` Constructor:
+
+```python
+data = dict(x=10, y=20)
+```
+
+### Creating an Empty Dictionary:
+
+```python
+empty = {}
+```
+
+## Accessing Dictionary Elements
+
+### Using Key Indexing:
+
+```python
+person["name"]
+```
+
+### Using `get()` Method:
+
+```python
+person.get("age")
+person.get("gender", "Not Found")
+```
+
+## Adding and Updating Items
+
+### Add New Key-Value:
+
+```python
+person["gender"] = "Female"
+```
+
+### Update Existing Key:
+
+```python
+person["age"] = 30
+```
+
+### Use `update()` Method:
+
+```python
+person.update({"age": 35, "city": "Chicago"})
+```
+
+## Removing Elements
+
+### Using `pop()`:
+
+```python
+person.pop("age")
+```
+
+### Using `del`:
+
+```python
+del person["city"]
+```
+
+### Using `clear()`:
+
+```python
+person.clear()
+```
+
+### Using `popitem()`:
+
+Removes and returns the last inserted key-value pair.
+
+```python
+person.popitem()
+```
+
+## Dictionary Methods
+
+| Method      | Description                                      |
+| ----------- | ------------------------------------------------ |
+| `get(key)`  | Returns value for key or `None` if key not found |
+| `keys()`    | Returns a view of all keys                       |
+| `values()`  | Returns a view of all values                     |
+| `items()`   | Returns a view of key-value pairs                |
+| `update()`  | Updates dictionary with another dictionary       |
+| `pop(key)`  | Removes specified key                            |
+| `popitem()` | Removes the last inserted item                   |
+| `clear()`   | Removes all elements                             |
+| `copy()`    | Returns a shallow copy                           |
+
+## Iterating Through a Dictionary
+
+### Loop Through Keys:
+
+```python
+for key in person:
+    print(key)
+```
+
+### Loop Through Values:
+
+```python
+for value in person.values():
+    print(value)
+```
+
+### Loop Through Key-Value Pairs:
+
+```python
+for key, value in person.items():
+    print(key, value)
+```
+
+## Nested Dictionaries
+
+A dictionary can contain other dictionaries as values, enabling hierarchical data storage.
+
+```python
+students = {
+    "101": {"name": "John", "grade": "A"},
+    "102": {"name": "Emma", "grade": "B"},
+}
+students["101"]["name"]  # Output: John
+```
+
+## Dictionary Comprehension
+
+Like list comprehensions, dictionary comprehensions offer a concise way to create dictionaries.
+
+```python
+squares = {x: x*x for x in range(1, 6)}
+```
+
+## Use Cases of Dictionaries
+
+* Representing JSON or structured data
+* Frequency counting (e.g., word count)
+* Lookup tables
+* Configuration or settings
+* Storing database records in memory
+
+## Dictionary vs List
+
+| Feature    | Dictionary               | List              |
+| ---------- | ------------------------ | ----------------- |
+| Structure  | Key-value pairs          | Indexed elements  |
+| Access     | Via key                  | Via index         |
+| Order      | Insertion ordered (3.7+) | Ordered           |
+| Mutability | Mutable                  | Mutable           |
+| Use Case   | Lookup, mapping          | Sequence of items |
+
+## Best Practices
+
+* Use `.get()` instead of direct key access to avoid `KeyError`.
+* Use dictionary comprehension for cleaner and more readable code.
+* Use keys that are hashable (e.g., strings, numbers).
+* Use dictionaries for fast lookups and structured data representation.
+
+## Summary
+
+* Dictionaries are one of the most versatile data structures in Python.
+* They store key-value pairs and allow fast retrieval based on keys.
+* Keys must be unique and immutable.
+* Dictionaries support powerful methods for data manipulation and traversal.

docs/python/setup-environment.md

@@ -2,7 +2,7 @@
 id: setup-environment
 title: Setting up your development environment
 sidebar_label: Setting up environment
-sidebar_position: 11
+sidebar_position: 12
 tags:
   [
     html,