Numbers and Variables in Python: Definitions

1. Definition and syntax

Type	Syntax	Structure
List	[1, "apple", True]	Ordered and mutable
Tuple	(1, "apple", True)	Ordered and immutable
Dictionary	{"name": "Ali", "age": 30}	Key–value mapping

2. Feature comparison

Feature	List	Tuple	Dictionary
Mutability	✅ Mutable	❌ Immutable	✅ Mutable
Access	By index (0, 1, ...)	By index	By unique key
Keeps order	✅ Yes	✅ Yes	✅ Since Python 3.7
Duplicates	✅ Allowed	✅ Allowed	Keys: ❌ / Values: ✅ allowed
Typical use	Dynamic collections	Fixed, grouped data	Mapping and fast lookup

3. Access examples

# List
my_list = ["apple", "banana", "cherry"]
print(my_list[0])      # Output: 'apple'

# Tuple
my_tuple = ("apple", "banana", "cherry")
print(my_tuple[1])     # Output: 'banana'

# Dictionary
my_dict = {"fruit1": "apple", "fruit2": "banana"}
print(my_dict["fruit2"])  # Output: 'banana'

4. When to use which?

• Lists: when you have a flexible collection that needs items added or changed.
• Tuples: for grouping fixed data such as coordinates or program constants.
• Dictionaries: when you need a fast mapping between keys and values, such as user profiles or app settings.

Conclusion

Understanding the differences between lists, tuples and dictionaries leads to cleaner, faster and more maintainable Python code. Choosing the right data structure for each job pays off in real projects.