Python Tuples

1. Define a tuple in Python

• A tuple in Python is an unmodifiable sequence of ordered data. This means that each element of the tuple is associated with a position (an index). The first element of a tuple has index 0 and the last element has index n - 1 for a list containing n elements. Unlike lists, tuples are not modifiable (immutable)
• Tuples are like lists: a tuple consists of different values ​​separated by commas. Note that we usually surround the values ​​of a tuple with a couple of parentheses even if this is not mandatory.
• Tuples can contain different types of values ​​like numbers, strings, lists etc. and even other nested tuples.
• The main difference between a tuple and a list is that a tuple is immutable data unlike a list which is alterable. This means that we will not be able to modify the values ​​of a tuple after its creation.
• It will therefore be interesting to use tuples rather than lists in cases where you want to ensure that the data is not modified in a program.

Example. Creating a tuple:

myTtuple = ("Java", "Python", "php")
print (myTuple)
# output: ('Java', 'Python', 'php')

2 - Access to the tuple elements

You can access the elements of a tuple by referring to the index number, enclosed in square brackets:

Example. Access the item in position 1:

myTuple = ("Java", "Python", "php")
print (myTuple [1])
# display: Python

Note  

Once a tuple is created, you can not change its values. The tuples are immutable.

3. Loop through a tuple

You can browse the elements of a tuple by using a for loop.

Example. Browse the elements and print the values:

myTuple = ("Java", "Python", "php")
for x in myTuple:
   print (x)
# Displays all elements of the tuple.

4. Check if an element exists in a tuple

To determine if a specified item is present in a tuple, you can use the keyword in:

Example. Check if "schoolbag" is present in the tuple:

myTuple = ("Java", "Python", "php")
print("javascript" in myTuple)# display false
print("Java" in myTuple)# display true

5. Length of a Python tuple

The length of a tuple is the number of its elements. To determine the length of a tuple in Python, we use the len() method:

Example. number of elements of a tuple:

myTuple = ("Java", "Python", "php")
print (len(myTuple))
# display 3

6. Unable to add or remove an item from a tuple

Note

Once a tuple is created, you can not add it any elements. The tuples are immutable.

Example. Unable to add an Item to a Tuple:

myTuple = ("Java", "Python", "php")
myTuple [3] = "Javascript" # This will cause an error!

7. Deleting a tuple

The tuples are not editable, so you can not delete items, but you can completely remove the tuple with the del key word:

Example. Delete a tuple completely:

myTuple = ("Java", "Python", "php")
del myTuple
print (myTuple) # this will generate an error because the tuple no longer exists

8. Creating a tuple by using the tuple constructor()

Example

myTuple = tuple(("binder", "notebook", "book"))
# note the double round parentheses
print (myTuple)

9. Methods associated with a tuple

Python has two built-in methods that you can use on tuples:

1. count () :  Returns the number of times a specified value appears in a tuple.
2. index () :  Searches the tuple for a specified value and returns the position of the place where it was found.