Merge pull request #104 from codewithdhruba01/string/chepter

feat(python-tutorial): add comprehensive 'String in Python' chapter

Author: sanjay-kv

docs/python/python-string.md

@@ -0,0 +1,197 @@
+---
+id: python-string
+title: String in Python
+sidebar_label: String in Python #displays in sidebar
+sidebar_position: 7
+tags:
+  [
+    Python,
+    Introduction of python,
+    Python Syntax,
+    Variables,
+    Operators,
+    Type Casting,
+    String
+  ]
+
+---
+
+In Python, a **string** is a sequence of characters enclosed within **single (`'`)**, **double (`"`)**, or **triple quotes (`''' '''` or `""" """`)**.  
+It is used to store and manipulate **textual data**.
+
+```python
+str1 = 'Hello'
+str2 = "World"
+str3 = '''This is a multi-line string.'''
+````
+
+## Creating Strings
+
+Strings can be created in several ways:
+
+```python
+name = "Dhruba"
+message = 'Welcome to Python'
+multiline = """This
+is a
+multiline string."""
+```
+
+## String Indexing and Slicing
+
+**Indexing**: Access characters by position (starting at index 0).
+
+```python
+text = "Python"
+print(text[0])   # P
+print(text[-1])  # n
+```
+
+**Slicing**: Extract a part of the string.
+
+```python
+print(text[0:3])   # Pyt
+print(text[::2])   # Pto
+print(text[1:-1])  # ytho
+```
+
+## String Methods
+
+| Method            | Description                          |
+| ----------------- | ------------------------------------ |
+| `upper()`         | Converts all characters to uppercase |
+| `lower()`         | Converts all characters to lowercase |
+| `strip()`         | Removes spaces from both ends        |
+| `replace(a, b)`   | Replaces `a` with `b`                |
+| `startswith(val)` | Checks if string starts with `val`   |
+| `endswith(val)`   | Checks if string ends with `val`     |
+| `find(val)`       | Finds the first index of `val`       |
+| `count(val)`      | Counts occurrences of `val`          |
+
+```python
+msg = " Hello Python "
+print(msg.upper())                 # HELLO PYTHON
+print(msg.strip())                 # Hello Python
+print(msg.replace("Python", "JS")) # Hello JS
+```
+
+## String Concatenation and Repetition
+
+**Concatenation** with `+`:
+
+```python
+first = "Hello"
+second = "World"
+print(first + " " + second)  # Hello World
+```
+
+**Repetition** with `*`:
+
+```python
+print("Hi! " * 3)  # Hi! Hi! Hi!
+```
+
+## Using `in` and `not in` Operators
+
+Check for substring presence:
+
+```python
+text = "Python is fun"
+print("fun" in text)      # True
+print("Java" not in text) # True
+```
+
+## String Formatting
+
+### f-string (Python 3.6+)
+
+```python
+name = "Dhruba"
+age = 22
+print(f"My name is {name} and I am {age} years old.")
+```
+
+### format() method
+
+```python
+print("My name is {} and I am {} years old.".format(name, age))
+```
+
+### % operator
+
+```python
+print("My name is %s and I am %d years old." % (name, age))
+```
+
+---
+
+## Escape Sequences
+
+Escape characters add special formatting in strings:
+
+| Escape | Meaning      |
+| ------ | ------------ |
+| `\n`   | New line     |
+| `\t`   | Tab space    |
+| `\\`   | Backslash    |
+| `\'`   | Single quote |
+| `\"`   | Double quote |
+
+```python
+print("Hello\nWorld")     # Line break
+print("Name:\tDhruba")    # Tab
+```
+
+
+## Multiline Strings
+
+Triple quotes allow multi-line text:
+
+```python
+message = """This is line 1
+This is line 2
+This is line 3"""
+print(message)
+```
+
+
+## Use Cases and Examples
+
+### Greet user
+
+```python
+name = input("Enter your name: ")
+print(f"Welcome, {name}!")
+```
+
+### Count letters
+
+```python
+text = "banana"
+print(text.count("a"))  # 3
+```
+
+### Read file and process
+
+```python
+with open("file.txt") as f:
+    data = f.read()
+    print(data.lower())
+```
+
+### Validate email domain
+
+```python
+email = "[email protected]"
+if email.endswith("@example.com"):
+    print("Valid domain")
+```
+
+
+## Summary
+
+* Strings are **immutable** sequences of characters.
+* Support **indexing**, **slicing**, **concatenation**, and **repetition**.
+* Useful **methods** help in text processing.
+* Use **escape sequences** for formatting.
+* Use **f-strings** or `format()` for clean formatting.

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: 7
+sidebar_position: 8
 tags:
   [
     html,