Tuple

Tuple data type:

A tuple is a collection of elements/items of different data types is called tuple.

A tuple is similar to list. Elements are separated by comma operator and enclosed within parentheses ().

Difference between list and tuple is: List elements can be modified as it is mutable. Whereas tuple elements can not be modified as it is immutable. So tuple is treated as a read-only list.

Syntax:

Variable=(item1,item2,….)

Example:

t=(10,-20,10,2.4,”raj”,”$”,True)

Individual elements of the tuple can be referenced using square braces as a[0],a[1]

Ex:

a=(10,20,30,40)#collection of items like arrays

a=(10,-20,12.5,'Ravi',"Sita") # A tuple may have different types like objects

a=(10,-20,10)  #duplication

a[1]=30 # Error

print(a[0]) à 10

a=(10,20,30,40)

print(a):-> (10,20,30,40)

print(a[1:3]) :-20,30

print(a[-1]):->40

print(a*2):-> 10,20,30,40,10,20,30,40

Ex1:

a=(10,20,30)

a[0]=40 #error as it is immutable

A tuple can be modified when we list is initialised in a tuple

Example:

>>> t=(2,3,[4,5])

>>> t[0]
2

>>> t[1]
3
>>> t[1]=7
>>>t[1]
7

>>> t[2]

[4, 5]

>>> t[2][0]=6

>>> print(t)

(2, 7, [6, 5])

>>> 

Creating a tuple with one element within parentheses is not enough. We should give comma separator to indicate it is tuple.

Ex:

>>> a=("ravi")

>>> type(a)

<class 'str'>

>>> a=("ravi",)

>>> type(a)

<class 'tuple'>

Individual elements can be accessed by using square brackets [ ].

>>> a=(10,20,30)

>>> a[0]

10

>>> a[1]

20

>>> a(0) # Error as to access any element we should use [ ]

Packing and unpacking tuples:

A tuple can also be created without using parentheses. This is called packing tuples

Ex:

>>> t=3,4,6,"ravi"

>>> print(t)

(3, 4, 6, 'ravi')

Unpacking:

>>> a,b,c,d=t

>>> a

3

>>> b

4

>>> c

6

>>> d

'ravi'

>>> a,b,c=t # Error because no of elements and no of variable should be matched.

1.  Slicing operation in Tuple:

We can access a range of items in a tuple by using the slicing operator (:)

Example:

a=(2,3,4,5)

print(a[1:3])

output:

(3,4)

2. Concatenation of tuple

We can use + operator to combine two tuples. This is called concatenation.

Ex:

>>> a=(2,4,6) #tuple a is created

>>> b=(7,2.4,8,True) #tuple b is created

>>> print(a+b)

(2, 4, 6, 7, 2.4, 8, True)

Ex2:

a=(10,20,30)

print(type(a)) #<class 'tuple'>

print(a)#(10, 20, 30)

print(id(a))#59342480

a=a+(40,)

print("after concatenation")

print(a)#(10, 20, 30, 40)

print(id(a))#66274000

3. Repeating the tuple elements

We can also repeat the elements in a tuple for a given number of times using the * operator.

Both + and * operations result in a new tuple

Example:

>>> a=(4,6,7)

>>> print(a*3)

(4, 6, 7, 4, 6, 7, 4, 6, 7)

4. Deleting the tuple

We can not change or delete the tuple elements. But deleting a tuple entirely is possible using the keyword ‘del’

Example:

a=(6,8,2,3)

>>> type(a)

<class 'tuple'>

>>> print(a)

(6, 8, 2, 3)

>>> del a[1] #Error

>>>a.remove(8) #Error

>>> del a # Valid, entire tuple a is deleted

5.  Converting into Tuple:

a=("ravi")# string

print(type(a))

b=str(a)

print(type(b))

c=tuple(b)#converting from string to tuple

print(type(c))

"""

<class 'str'>

<class 'str'>

<class 'tuple'>

"""

Tuple Membership:

We can test if an item exists in a tuple or not, using the keywords :

in, not in

>>> t=('c','a','t')

>>> print('a' in t)

True

>>> print(a in t) #Error

>>> print('t' in t)

True

>>> print('j' not in t)

True

>>> print('a' not in t)

False

#To get the nth element from last of a tuple using positive and -ve index

a=("r","a","j","e","n","d","r","a")

print(type(a))#tuple

#get 4th element of the tuple by index

n=a[3]

print(n)#e

#get 4 :nth element from last by negative index

print(a[-4])#n

Advantages of tuple over list:

Since tuples are similar to lists, both of them are used in similar situations.

We generally use tuple for different data types (Heterogeneous) and list for homogeneous (same data type)

Difference between Lists and Tuples

List	Tuple
The elements of a list are mutable	elements of a tuple are immutable
When we need to change the data in future, list would be a right data type.	When we do not want to change the data over time, the tuple is a preferred data type
When we are iterating (in looping statements) elements, performance is slow	Iterating over the elements of a tuple is faster .
The elements of list are enclosed in square bracket.          Ex: a=[10,20,30,40]	Elements of a tuple are enclosed in parenthesis Ex: a=(10,20,30,40)

Since tuples are immutable, tuple is faster than list so there is a slight performance

Assignments:

(1.) a = (1, 2, 4, 3), which of the following is incorrect?
a) print(a[3])
b) a[3] = 45
c) print(max(a))
d) print(len(a))

Answer: b

(2.) What will be the output?

>>>t=(1,2,4,3)

>>>t[1:-1]

a) (1, 2)

b) (1, 2, 4)

c) (2, 4)

d) (2, 4, 3)

Answer: c

(3.)  What will be the output?

>>>t = (1, 2)

>>>2 * t

a) (1, 2, 1, 2)

b) [1, 2, 1, 2].

c) (1, 1, 2, 2)

d) [1, 1, 2, 2].

Answer: a

Next topic: Set data type

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