Python List
In Python lists allows us to store a sequence of items in a single variable.
Create a Python list
We create a list by placing elements inside square brackets [], separated by commas. For example,
# a list of three elements
ages = [19, 26, 29]
print(ages)
# Output: [19, 26, 29]
List Characteristics
Lists are:
- Ordered – They maintain the order of elements.
- Mutable – Items can be changed after creation.
- Allow duplicates – They can contain duplicate values.
Access List Elements
Each element in a list is associated with a number, known as a index.
The index always starts from 0. The first element of a list is at index 0, the second element is at index 1, and so on.
List → ['Python', 'Swift', 'C++']
Index → 0 1 2
Index of List Elements
Negative Indexing in Python
Python also supports negative indexing. The index of the last element is -1, the second-last element is -2, and so on.
[‘Python’, ‘Swift’, ‘C++’]
Index → 0 1 2
Negative Index → -3 -2 -1
Python Negative Indexing
Negative indexing makes it easy to access list items from last.
Let’s see an example,
languages = ['Python', 'Swift', 'C++']
# access item at index 0
print(languages[-1]) # C++
# access item at index 2
print(languages[-3]) # Python
Slicing of a List in Python
In Python, it is possible to access a section of items from the list using the slicing operator :. For example,
my_list = ['p', 'r', 'o', 'g', 'r', 'a', 'm']
# items from index 2 to index 4
print(my_list[2:5])
# items from index 5 to end
print(my_list[5:])
# items beginning to end
print(my_list[:])
Output:
['o', 'g', 'r']
['a', 'm']
['p', 'r', 'o', 'g', 'r', 'a', 'm']