Data structures in Python are used to organize and store data efficiently. Python provides several built-in data structures, each serving specific purposes. Understanding these structures is essential for effective programming. Here are some key data structures in Python:
Lists:
A list is a versatile and mutable data structure that can hold elements of different data types. Lists are created using square brackets [].
my_list = [1, 2, 3, "apple", "banana", True]Common Operations:
- Accessing Elements:
my_list[0] - Slicing:
my_list[1:4] - Appending:
my_list.append(4) - Inserting:
my_list.insert(2, "orange") - Removing:
my_list.remove("banana")
Tuples:
Tuples are similar to lists but are immutable (cannot be modified after creation). They are created using parentheses ().
my_tuple = (1, 2, 3, "apple", "banana")Common Operations:
- Accessing Elements:
my_tuple[0] - Slicing:
my_tuple[1:4] - Concatenation:
new_tuple = my_tuple + (4, 5)
Sets:
Sets are unordered collections of unique elements. They are created using curly braces {} or the set() constructor.
my_set = {1, 2, 3, "apple", "banana"}Common Operations:
- Adding Elements:
my_set.add(4) - Removing Elements:
my_set.remove("banana") - Set Operations: Union, Intersection, Difference
Dictionaries:
Dictionaries are key-value pairs, allowing efficient data retrieval. They are created using curly braces {}.
my_dict = {"name": "John", "age": 25, "city": "New York"}Common Operations:
- Accessing Values:
my_dict["name"] - Modifying Values:
my_dict["age"] = 26 - Adding New Key-Value Pairs:
my_dict["gender"] = "Male" - Removing Key-Value Pairs:
del my_dict["city"]
Strings:
Strings are sequences of characters. They are immutable, and you can use single (') or double (") quotes to define them.
my_string = "Hello, Python!"Common Operations:
- Concatenation:
new_string = "Hello" + " " + "World" - Slicing:
substring = my_string[7:13] - Length:
length = len(my_string) - Formatting:
"Name: {}, Age: {}".format(name, age)
Arrays:
Arrays are similar to lists but are specialized for numerical data. They are provided by the array module.
from array import array
my_array = array("i", [1, 2, 3, 4, 5])Queues and Stacks:
Queues and stacks are abstract data types. Queues follow the First In, First Out (FIFO) principle, while stacks follow the Last In, First Out (LIFO) principle. These can be implemented using lists or collections from the queue module.
Linked Lists:
Linked lists are a collection of nodes where each node points to the next node in the sequence. They are not built into Python but can be implemented using classes.
Custom Classes:
You can create your own data structures using classes. This allows you to define the structure and behavior of your data as needed.
Understanding when to use each data structure is crucial for writing efficient and maintainable code. The choice of a data structure depends on the specific requirements and operations performed on the data.