Python Tuples

1 - Define a tuple in Python

A tuple is an orderly and non-modifiable collection (n-tuples in mathematics). In Python, tuples are written with parentheses.

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()

Another way to create a tuple is to use 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.  

Younes Derfoufi
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