#PYTHON(DAY8)tuple and it's methods

 

#PYTHON(DAY8)

Tuple and It’s methods

Tuple()

• Tuples are sequential, indexable, heterogeneous containers which are immutable in nature
• ‘( )’ are used to represent a tuple, tuple can never be empty, it takes atleast 2 values
• a tuple with one element can be created using ‘,’ and passing no second element
• there are two methods we can perform on tuple
• we can use tuple as unpack
• tuples are faster when compared to list

Example:

mytuple = ("apple", 1,2)
print(mytuple)

And the output is:

('apple',1,2)

So, to know the type of class we use type() function

x = (1,2,3,1,'sree',4)
print(x)
print(type(x))

And the expected output is:

(1,2,3,1,'sree',4)
<class 'tuple'>

Tuple Length

To determine how many items a tuple has, use the len() function

thistuple = ("apple", "banana", "cherry")
print(len(thistuple))

And the expected output is:

3

creating an empty tuple

x = ()
print(x, len(x), type(x), sep = '\n')

And the expected output is:

()
0
<class 'tuple'>

creating a tuple with 2 elements

x = (1,)
print(x, len(x), type(x), sep = '\n')

And the expected output is:

(1,)
1
<class 'tuple'>

NOTE: tuple does not contain a single element

x = (1)
print(x, len(x), type(x), sep = '\n')

we get an error for this as: object of type ‘int’ has no len()

type-casting

converting list to tuple

a = [1,2,3]
x = tuple(a)
print(x, len(x), type(x), sep = '\n')

And the expected output is:

(1, 2, 3)
3
<class 'tuple'>

converting string to tuple

a = 'generic string'
x = tuple(a)
print(x, len(x), type(x), sep = '\n')

And the expected output is:

('g', 'e', 'n', 'e', 'r', 'i', 'c', ' ', 's', 't', 'r', 'i', 'n', 'g')
14
<class 'tuple'>

Access Tuple Items

You can access tuple items by referring to the index number, inside square brackets:

thistuple = ("apple", "banana", "cherry")
print(thistuple[1])

And the expected output is:

banana

The first item has index as 0

Negative Indexing

Negative indexing means start from the end.

-1 refers to the last item, -2 refers to the second last item etc.

thistuple = ("apple", "banana", "cherry")
print(thistuple[-1])

And the output is:

cherry

Methods in tuple():

1. index()
2. count()

Range of Indexes

You can specify a range of indexes by specifying where to start and where to end the range.

When specifying a range, the return value will be a new tuple with the specified items.

x = ('apple','banana','grapes','mango','orange','kiwi')
print([2:5])

And the expected output is:

('grapes','mango','orange')

Note: The search will start at index 2 (included) and end at index 5 (not included).

By leaving out the start value, the range will start at the first item:

thistuple = ("apple", "banana", "cherry", "orange", "kiwi", "melon", "mango")
print(thistuple[:4])

And the expected output is:

('apple', 'banana', 'cherry', 'orange')

Range of Negative Indexes

Specify negative indexes if you want to start the search from the end of the tuple:

This example returns the items from index -4 (included) to index -1 (excluded)

thistuple = ("apple", "banana", "cherry", "orange", "kiwi", "melon", "mango")
print(thistuple[-4:-1])

And the expected output is:

('orange', 'kiwi', 'melon')

Check if Item Exists

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

Check if “apple” is present in the tuple:

thistuple = ("apple", "banana", "cherry")
if "apple" in thistuple:
  print("Yes, 'apple' is in the fruits tuple")

And the expected output is:

Yes, 'apple' is in the fruits tuple

count()

Returns the number of times the value appears in the tuple

thistuple = (1, 3, 7, 8, 7, 5, 4, 6, 8, 5)

x = thistuple.count(5)

print(x)

And the expected output is:

2

Unpacking a tuple

we can also extract the values back into variables. This is called “unpacking”

fruits = ("apple", "banana", "cherry")

(green, yellow, red) = fruits

print(green)
print(yellow)
print(red)

And the expected output is:

apple
banana
cherry