Tuple in Python: 11th Class Computer Science Chapter 08

Chapter Name:	Tuple in Python [Chapter 08]
Class:	11th
Subject:	Computer Science

8.1 INTRODUCTION: Tuple in Python

• Tuple is a collection of elements which is ordered and unchangeable (Immutable).
• Immutable means you cannot change elements of a tuple in place.
• Allows duplicate members.
• Consists the values of any type, separated by comma.
• Tuples are enclosed within parentheses ( ).
• Cannot remove the element from a tuple.

8.2 Creating Tuple:

Syntax:
tuple-name = ( ) # empty tuple
tuple-name = (value-1, value-2, …….. , value-n)

Example:
>>> T=(23, 7.8, 64.6, ‘h’, ‘say’)
>>> T
(23, 7.8, 64.6, ‘h’, ‘say’)

8.2.1 Creating a tuple with single element:

>>> T=(3)             #With a single element without comma, it is a value only, not a tuple
>>> T
3
>>> T= (3, )          # to construct a tuple, add a comma after the single element
>>> T
(3,)

>>> T1=3, # It also creates a tuple with single element
>>> T1
(3,)

8.2.2 Creating a tuple using tuple( ) constructor:

It is also possible to use the tuple( ) constructor to create a tuple.

>>>T=tuple( ) # empty tuple
>>> T=tuple((45,3.9, ‘k’,22)) #note the double round-brackets
>>> T
(45, 3.9, ‘k’, 22)
>>> T2=tuple(‘hello’) # for single round-bracket, the argument must be of sequence type
>>> T2
(‘h’, ‘e’, ‘l’, ‘l’, ‘o’)
>>> T3=(‘hello’,’python’)
>>> T3
(‘hello’, ‘python’)

8.2.3 Nested Tuples:

>>> T=(5,10,(4,8))
>>> T
(5, 10, (4, 8))

8.2.4 Creating a tuple by taking input from the user:

>>> T=tuple(input(“enter the elements: “))
enter the elements: hello python
>>> T

(‘h’, ‘e’, ‘l’, ‘l’, ‘o’, ‘ ‘, ‘p’, ‘y’, ‘t’, ‘h’, ‘o’, ‘n’)

>>> T1=tuple(input(“enter the elements: “))

enter the elements: 45678

>>> T1 (‘4’, ‘5’, ‘6’, ‘7’, ‘8’)                                 # it treats elements as the characters though we entered digits

To overcome the above problem, we can use eval( ) method, which identifies the data type and evaluate them automatically.

>>> T1=eval(input(“enter the elements: “))

enter the elements: 56789

>>> T1 56789                                                     # it is not a list, it is an integer value

>>> type(T1) <class ‘int’>

>>> T2=eval(input(“enter the elements: “))

enter the elements: (1,2,3,4,5)                          # Parenthesis is optional

>>> T2 (1, 2, 3, 4, 5)

>>> T3=eval(input(“enter the elements: “))

enter the elements: 6, 7, 3, 23, [45,11]             # list as an element of tuple

>>> T3 (6, 7, 3, 23, [45, 11])

8.3 Accessing Tuples: Tuple in Python

Tuples are very much similar to lists. Like lists, tuple elements are also indexed. Forward indexing as 0,1,2,3,4……… and backward indexing as -1,-2,-3,-4,………

• The values stored in a tuple can be accessed using the slice operator ([ ] and [:]) with indexes.
• tuple-name[start:end] will give you elements between indices start to end-1.
• The first item in the tuple has the index zero (0).

Example:

>>> alpha=(‘q’,’w’,’e’,’r’,’t’,’y’)

>>> alpha[5] ‘y’
>>> alpha[-4] ‘e’
>>> alpha[46]

IndexError: tuple index out of range

>>> alpha[2]=’b’ #can’t change value in tuple, the value will remain unchanged

TypeError: ‘tuple’ object does not support item assignment

8.3.1 Difference between List and Tuple:

8.4 Traversing a Tuple: Tuple in Python

Syntax:

for in tuple-name:
statement

Example:

Method-1

>>> alpha=(‘q’,’w’,’e’,’r’,’t’,’y’)
>>>for i in alpha:
print(i)

Output:

q
w
e
r
t
y

Method-2:

>>> for i in range(0, len(alpha)):
print(alpha[i])

Output:

q
w
e
r
t
y

8.5 Tuple Operations:

• Joining operator +
• Repetition operator *
• Slice operator [ : ]
• Comparison Operator <, <=, >, >=, ==, !=

1) Joining Operator: It joins two or more tuples.

Example:
>>> T1 = (25,50,75)
>>> T2 = (5,10,15)
>>> T1+T2
(25, 50, 75, 5, 10, 15)

>>>T1 + (34)
TypeError: can only concatenate tuple (not “int”) to tuple

>>> T1 + (34, )
(25, 50, 75, 34)

2)Repetition Operator: It replicates a tuple, specified number of times.

Example:
>>> T1*2
(25, 50, 75, 25, 50, 75)
>>> T2=(10,20,30,40)
>>> T2[2:4]*3
(30, 40, 30, 40, 30, 40)

3)Slice Operator: tuple-name[start:end] will give you elements between indices start to end-1.

>>>alpha=(‘q’,’w’,’e’,’r’,’t’,’y’)
>>> alpha[1:-3] (‘w’, ‘e’)
>>> alpha[3:65] (‘r’, ‘t’, ‘y’)
>>> alpha[-1:-5]

( )
>>> alpha[-5:-1] (‘w’, ‘e’, ‘r’, ‘t’)

List-name[start:end:step] will give you elements between indices start to end-1 with
skipping elements as per the value of step.

>>>alpha[1:5:2] (‘w’, ‘r’)
>>> alpha[ : : -1] (‘y’, ‘t’, ‘r’, ‘e’, ‘w’, ‘q’) #reverses the tuple

4)Comparison Operators:

• Compare two tuples
• Python internally compares individual elements of tuples in lexicographical
  order.
• It compares the each corresponding element must compare equal and two
  sequences must be of the same type.
• For non-equal comparison as soon as it gets a result in terms of True/False,
  from corresponding elements’ comparison. If Corresponding elements are
  equal, it goes to the next element and so on, until it finds elements that differ

Example:
>>> T1 = (9, 16, 7)
>>> T2 = (9, 16, 7)
>>> T3 = (‘9′,’16’,’7′)
>>> T1 = = T2
True
>>> T1==T3
False
>>> T4 = (9.0, 16.0, 7.0)
>>> T1==T4
True
>>> T1<T2
False
>>> T1<=T2
True

8.6 Tuple Methods:

Consider a tuple:
subject=(“Hindi”,”English”,”Maths”,”Physics”)

 

8.7 Tuple Packing and Unpacking: Tuple in Python

Tuple Packing: Creating a tuple from set of values.

Example:
>>> T=(45,78,22)
>>> T
(45, 78, 22)

Tuple Unpacking : Creating individual values from the elements of tuple.

Example:
>>> a, b, c=T
>>> a
45
>>> b
78
>>> c
22

Note: Tuple unpacking requires that the number of variable on the left side must be equal
to the length of the tuple.

8.8 Delete a tuple:

The del statement is used to delete elements and objects but as you know that tuples are immutable, which also means that individual element of a tuple cannot be deleted.

Example:
>> T=(2,4,6,8,10,12,14)
>>> del T[3] TypeError: ‘tuple’ object doesn’t support item deletion

But you can delete a complete tuple with del statement as:

Example:
>>> T=(2,4,6,8,10,12,14)
>>> del T
>>> T

NameError: name ‘T’ is not defined