[Add]: Variable and Literals

Author: gauravfs-14

docs/python-basics/variable-literal.md

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+---
+sidebar_position: 3
+---
+
+# Variable And Literal
+
+## Literals:
+
+### Definition
+
+Fixed values directly written in the code.
+
+### Examples
+
+1. **Numbers**: 4, 102, -21, 4_000_000 (underscores for readability).
+2. **Booleans**: True or False.
+3. **Text**: "python" or 'This language is fun!'.
+4. **Lists**: [1, 2, 3].
+
+## Variables:
+
+### Definition
+
+Names that store values in memory.
+
+### Creation
+
+Use a name, =, and a value (e.g., price = 45.50).
+
+### Naming Rules
+
+Use letters, numbers, or underscores without spaces. Must start with a letter or underscore.
+
+## Data Types:
+
+1. **Integer**: Whole numbers (e.g., -2, 0, 23).
+2. **Float**: Numbers with decimals (e.g., 3.14, -0.001).
+3. **Boolean**: True or False.
+4. **String**: Text (e.g., "Thailand").
+5. **NoneType**: Represents no value (None).
+
+## Type Function:
+
+### Usage
+
+Check the type of a value (e.g., type(4) returns int).
+
+## Type Casting:
+
+### Definition
+
+Changing a value from one type to another.
+
+### Examples
+
+1. **String to Float**: float("4.5").
+2. **Float to Integer**: int(3.14) (removes decimal).
+3. **String to Boolean**: bool("") is False, any other string is True.
+
+## Code Example
+
+```python title="example.py"
+# Numeric literals
+price = 45.50
+age = 24
+
+# Boolean literal
+is_printed = True
+
+# String literal
+course_name = "Python for Beginners"
+
+# Performing an operation with a variable
+tax = price * 0.09
+
+# Receiving input from the console
+user_input = input("Enter a number: ")
+
+# Type casting the input to a float
+user_number = float(user_input)
+
+# Printing the results
+print("Price:", price)
+print("Age:", age)
+print("Is Printed:", is_printed)
+print("Course Name:", course_name)
+print("Tax:", tax)
+print("User Number:", user_number)
+```