Tuples

Python's tuple data structure is immutable, meaning we cannot change the elements of the tuples. Basically, a tuple is a sequence of values that are separated by commas and are enclosed in parentheses ( ). Like lists, tuples are an ordered sequence of elements:

>>> t1 = 'h', 'e', 'l', 'l', 'o'

Tuples are enclosed in parentheses ( ):

>>> t1 = ('h', 'e', 'l', 'l', 'o')

You can also create a tuple with a single element. You just have to put a final comma in the tuple:

>>> t1 = 'h',
>>> type(t1)
<type 'tuple'>

A value in parentheses is not a tuple:

>>> t1 = ('a')
>>> type(t1)
<type 'str'>

We can create an empty tuple using the tuple() function:

>>> t1 = tuple()
>>> print (t1)
()

If the argument is a sequence (string, list, or tuple), the result is a tuple with the elements of the sequence:

>>> t = tuple('mumbai')
>>> print t
('m', 'u', 'm', 'b', 'a', 'i')

Tuples have values between parentheses ( ) separated by commas:

>>> t = ('a', 'b', 'c', 'd', 'e')
>>> print t[0]
'a'

The slice operator selects a range of elements.

>>> print t[1:3]
('b', 'c')

Accessing values in tuples

To access values in a tuple, use the square brackets for slicing along with the index or indices to obtain the value available at that index or indices, as shown in the following example:

#!/usr/bin/python3
cities = ('Mumbai', 'Bangalore', 'Chennai', 'Pune')
numbers = (1, 2, 3, 4, 5, 6, 7)
print (cities[3])
print (numbers[1:6])

Output:
Pune
(2, 3, 4, 5)

Updating tuples

Tuple updating is not possible in Python, as tuples are immutable. But you can create a new tuple with an existing tuple, as shown in the following example:

#!/usr/bin/python3
cities = ('Mumbai', 'Bangalore', 'Chennai', 'Pune')
numbers = (1,2,3,4,5,6,7)
tuple1 = cities + numbers
print(tuple1)

Output:
('Mumbai', 'Bangalore', 'Chennai', 'Pune', 1, 2, 3, 4, 5, 6, 7)

Deleting tuple elements

We cannot remove individual tuple elements. So, to remove an entire tuple explicitly, use the del statement. Refer to the following example:

#!/usr/bin/python3
cities = ('Mumbai', 'Bangalore', 'Chennai', 'Pune')
print ("Before deleting: ", cities)
del cities
print ("After deleting: ", cities)

Output:
Before deleting: ('Mumbai', 'Bangalore', 'Chennai', 'Pune')
Traceback (most recent call last):
File "01.py", line 5, in <module>
print ("After deleting: ", cities)
NameError: name 'cities' is not defined

Basic tuple operations

Like lists, there are five basic tuple operations:

• Concatenation
• Repetition
• Length
• Membership
• Iteration

Description	Expression	Results
Iteration	for x in (45,58,99) : print (x,end = ' ')	45 58 99
Repetition	('Python') * 3	('python', 'python', 'python')
Length	len(45, 58, 99, 65)	4
Concatenation	(30, 50, 60) + ('Hello', 75, 66)	(30,50,60,'Hello',75,66)
Membership	45 in (45,58,99,65)	True

Indexing, slicing, and matrices

Tuple indices work the same way as list indices. Values can be accessed using index. If you try to read or write an element that does not exist, you get IndexError. If an index has a negative value, it counts backward from the end of the list.

Now, we will create a tuple named cities and perform some index operations:

cities = ('Mumbai', 'Bangalore', 'Chennai', 'Pune')

Description	Expression	Results
Index starts at zero	cities[2]	'Chennai'
Slicing: getting sections	cities[1:]	('Bangalore', 'Chennai', 'Pune')
Negative: count from the right	cities[-3]	'Bangalore'

max() and min()

Using the max() and min() functions, we can find the highest and lowest values from the tuple. These functions allow us to find out information about quantitative data. Let's look at an example:

>>> numbers = (50, 80,98, 110.5, 75, 150.58)
>>> print(max(numbers))
150.58
>>>

Using max(), we will get the highest value in our tuple. Similarly, we can use the min() function:

>>> numbers = (50, 80,98, 110.5, 75, 150.58)
>>> print(min(numbers))
50
>>>

So, here we are getting the minimum value.