According to its definition, "A tuple is a finite sequence (also known as an "ordered list") of objects, each of a specified type." In other words, a tuple is an ordered collection of objects of different types. In Python, a tuple is a list of comma-separated values but immutable, unlike a list. So the operations on a tuple are restricted to the ones that don't affect its immutability. Accordingly, the following are the operations that can be performed on a tuple:
Due to a tuple's immutability, deletion and addition of new elements are not possible.
Creation: Creating or defining a tuple is as simple as giving a list of values within parenthesis. For example
>>> tup = (2, 4, 6, 8, 10)
is a tuple. If a tuple has only one element, it would be defined as follows:
>>> tup = (5,)
Accessing: Since lists and tuples are almost the same, the accessing mechanisms also work in a similar fashion. Elements of a tuple can be accessed in two ways:
Index based: The elements of a tuple can be accessed using their indices. The index starts at 0. For example, to access an element at index 0 of a tuple tup, the statement would be:
Slicing: As with a list, slice operator can be used to access elements of a tuple. It selects a range of elements. For example the following statement selects elements between 1 and 3 (excluding 3):
>>> tup[1:3] ('b', 'c')
That covers operations on a tuple. So the question arises, when do you use a list and when do you use a tuple? A list can be used in almost all cases. However, there are certain contexts where a tuple is more useful. These are:
When you need speed. Tuples are faster than lists. If you're defining a constant set of values and all you're ever going to do with it is iterate through it, use a tuple instead of a list.
When your data will not change. It makes your code safer if you "write-protect" data that does not need to be changed. Using a tuple instead of a list is like having an implied assert statement that this data is constant, and that special thought (and a specific function) is required to override that.
In all other contexts, lists can be used. That brings us to the next section, which is a real world example using a list.