Day 5: Python Syntax: Basic Concepts — List in detail

Python in 30 Days: A Practical and Theoretical Approach for Beginner.

A list is one of the most commonly used data structures in Python.

It is a collection of ordered, mutable (changeable), and heterogeneous elements.
Lists allow you to store multiple items in a single variable.
Lists are defined by square brackets [].

Table of Contents

Characteristics of Lists:

Ordered: The items in a list have a specific order, and this order is maintained.
Mutable: You can change the elements in a list (add, remove, modify).
Heterogeneous: A list can store elements of different data types (e.g., integers, strings, or even other lists).

SYNTAX

list_name = [element1, element2, element3, ...]

Example of List in Python

Creating a List

# Creating a List
fruits = ["apple", "banana", "cherry", "orange"]

Accessing elements by index (starting from 0)

print(fruits[0])  # Output: apple
print(fruits[2])  # Output: cherry

Negative indexing (accessing from the end of the list)

print(fruits[-1])  # Output: orange
print(fruits[-2])  # Output: cherry

Slicing a list

print(fruits[1:3])  
#Output: ['banana', 'cherry'] (items at index 1 and 2)

Modifying an element in the list

fruits[1] = "blueberry"
print(fruits)  
#Output: ['apple', 'blueberry', 'cherry', 'orange']

Adding an element to the list using append()

fruits.append("grape")
print(fruits)  
#Output : ['apple', 'blueberry', 'cherry', 'orange', 'grape']

Inserting an element at a specific position

fruits.insert(2, "kiwi")
print(fruits)  
# Output: ['apple', 'blueberry', 'kiwi', 'cherry', 'orange', 'grape'];

Removing an element from the list

fruits.remove("cherry")
print(fruits)  
# Output: ['apple', 'blueberry', 'kiwi', 'orange', 'grape']

Popping an element (removes the last item by default)

# Popping an element (removes the last item by default)
popped_item = fruits.pop()
print(popped_item)  # Output: grape
print(fruits)  
# Output: ['apple', 'blueberry', 'kiwi', 'orange']

Length of the list

# Length of the list
print(len(fruits))  
# Output: 4

Check if an item exists in the list

# Check if an item exists in the list
print("kiwi" in fruits)  
# Output: True
print("mango" in fruits)  
# Output: False

Lists in Python are versatile and easy to use.

They are the go-to structure for many tasks, such as storing and manipulating collections of data.

We can easily access, modify, and perform operations like appending, inserting, and removing elements with just a few lines of code.