In Python, lists support element indexing. Therefore, in this case, we can access all the elements in the list using their indices. In lists, indexing starts from 0. That is, the first element has index 0, the second has index 1, and so on.

list_A = ['red', 'green', 'blue', 'yellow', 'black']
# Getting the first element
print(list_A[0])

list_A = ['red', 'green', 'blue', 'yellow', 'black']
# Getting the third element
print(list_A[2])

We've talked about the usual indexing. But besides this, there is also negative indexing. Negative indexing means starting from the end, i.e. index -1 refers to the last element, index -2 refers to the penultimate element, and so on.

list_A = ['red', 'green', 'blue', 'yellow', 'black']
# Getting the last element
print(list_A[-1])

list_A = ['red', 'green', 'blue', 'yellow', 'black']
# Getting the fourth element
print(list_A[3], list_A[-2])

What is a list? A list is a collection that is ordered and changeable. Moreover, this collection allows duplicate elements.

What is a dictionary? A dictionary is an ordered and changeable collection with no duplicate members. A dictionary holds `key:value` pairs. Key-value is provided in the dictionary to make it more optimized. 

What is a tuple? A tuple is a collection that is ordered and unchangeable. This collection allows duplicate elements. A tuple is a collection that is very similar to a list. The sequence of values stored in a tuple can be of any type, and they are indexed by integers. Values of a tuple are syntactically separated by ‘commas’. Although it is not necessary, it is more common to define a tuple by closing the sequence of values in parentheses. This helps to understand the Python tuples more easily.

What is a set? In Python, a `set` is an `unordered collection` of data type that is `iterable`, `mutable` and has `no duplicate elements`. The order of elements in a set is undefined, though it may consist of various elements. The major advantage of using a set as opposed to a list is that it has a highly optimized method for checking whether a specific element is contained in the set.

Python Data Structures

List Indexing

Task