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()
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:
- count () : Returns the number of times a specified value appears in a tuple.
- index () : Searches the tuple for a specified value and returns the position of the place where it was found.
Younes Derfoufi
my-courses.net