Tuples

A Tuple is also an ordered collection of elements just like lists, but tuples are immutable. So you can not change the elements of a tuple after it is assigned (unlike lists where you are allowed to do so). This immutable nature makes tuples very useful when you don’t want your data to be mutated through out the program. Along with this, tuples are generally used to store elements of different data types. Where you defined a list using square brackets ([]), a tuple can be created by placing all the elements inside parentheses (), separated by commas.

#creating a tuple of two elements of String type 
my_tuple = ('apple', 'orange')

Tuple can also have elements of different types.

#A tuple having elements of different data types
my_tuple = ('apple', 1, 4.5)

Accessing the elements of a tuple

We can access the elements of a tuple by using indexes inside square bracket [] just like list. Also, just like lists, the index starts from 0.

#creating a tuple of three elements of String type 
my_tuple = ('apple', 'orange', 'mango')

print(my_tuple[0]) ## prints apple
print(my_tuple[2]) ## prints mango

Combine two tuples

We can combine two tuples by using + operator.

fruits = ('apple', 'orange', 'mango')
numbers = (1, 2, 3)

#Combine two tuples fruits and numbers
combined_tuple = fruits + numbers

print(combined_tuple) ## prints ('apple', 'orange', 'mango', 1, 2, 3)

Length of a tuple

len(tuple) function gives the number of elements present in the tuple.

fruits = ('apple', 'orange', 'mango')

print(len(fruits))  ## prints 3

Reassign a tuple

Since tuples are immutable, we can not change an element of the tuple. So fruits[0] = 'lemon' will give an error as here we are trying to change the element at index 0 of ‘fruits’. But we can reassign a tuple (replace the entire tuple).

my_tuple = ('apple', 'orange', 'mango')

print(my_tuple)  ## prints ('apple', 'orange', 'mango')

# ressigning my_tuple
my_tuple = (1, 2, 3) 

print(my_tuple)  ## prints (1, 2, 3)

Deleting a tuple

We can delete a tuple entirely using the keyword del.

fruits = ('apple', 'orange', 'mango')

print(fruits)  ## prints ('apple', 'orange', 'mango')

# Deleting fruits
del fruits 

print(fruits)  ## Gives ERROR as tuple fruits is no longer present 

Challenge

Let’s try the same exercise we just did with Lists, but using Tuples.

Start with the list of fruits below. Print out the list of fruits and for each fruit, as the user if they like it. If they like it, keep it. If they do not, remove it from the list. Next, ask the user to add a fruit that is missing from the list. Add it to the list and print out the number of fruits the user likes.

fruits = ['orange', 'kiwi', 'banana', 'apple', 'mango', 'lemon']