The document provides an introduction to Python data types, including numeric, boolean, string, list, tuple, and dictionary types. Participants will learn how to explain these data types, their usages, and characteristics, such as mutability of lists versus tuples. It includes code examples demonstrating each data type and basic operations.

1. Introduction to Python
Data Types
Vijaya Lakshmi A
Assistant
Professor
Department of CSE

2. Session
Objectives
2 v 1.2
• Learning python data
types

3. Session
Outcomes
3 v 1.2
• At the end of this session, participants will be
able to
– Explain Python data types

4. 4 v 1.2
Agend
a
• Python Data Types
– Numeric
– None
– Boolean
– String
– List
– Tuple
– Dictionary

5. Python Data Types
5 v 1.2
• There are different data types in Python:
• Numeric - Int, Float, Complex
Boolean
• Sequence - List, Tuple and String
Set
• Mapping - Dictionary None

6. 17 v 1.2
Numeric - Int, float, Complex
• Numeric can be Int, float and Complex types
• Numbers (both +ve and -ve) can be integers (int),
fractional
numbers (float) and complex numbers (complex)
x= 4 , y=- 3
Z = 256.25
a = 5 + 10 j
• The type of value depends upon the value
stored and no explicit
declaration is allowed.
>>>i = 9
>>>p r i n t ( t y p e ( i ) )
<c l a s s ’ i n t
’>
>>>i = 9. 78
>>>p r i n t ( t y p e ( i ) )
<c l a s s ’ f l o a
t ’>
>>> p r i n t ( t y p e ( a )
)
< c l a s s ’ complex ’>
o

7. Int and Float
7 v 1.2
• On typing a large number comma
>>>p r i n t ( 42000
) 42000
32
)
>>>p r i n t ( 42 , 0 0 , 0 00 )
42 0 0 # comma sseparated sequence
of integer
• The print function can print any number of values as long as
they are separate by commas.
>>>print ( 42 , 17 , 56 , 34 ,
11 , 4 . 3 5 ,
42 17 56 34 11 4 . 3 5 32
>>> p r o
i n ti
(t o
3 .
4h
,
3 . 4 h el l o 45
o b
20
2 2
” h el l o ” , 4
5 )

8. Complex Numbers
8 v 1.2
>>> a= 5+ 10 j
>>> t y p e ( a )
<c l a s s ’ complex ’
>
>>> b= 6
>>> compl ex ( b )
( 6 + 0 j )

9. None
9 v 1.2
• The None keyword is used to define a null value, or no value at
all.
• None is not the same as 0, False, or an empty string.
•None is a data type of its
own X=None
pr i n t ( X )
None
type( X )
<c l a s s ”NoneType” >

10. 21 v 1.2
Boolean
• It returns either True or False
>>>x=5
>>>y=x
>>>p r i n t ( x= = y )
Tr u e
>>>p r i n t ( x
<5) F a l s e
• Falsy and Truthy
values: When a value
evaluates to True, it’s
truthy. And
if a value evaluates to
False, it’s falsy.

11. 22 v 1.2
Boolean
Statements Return Value
print(bool(False)) False
print(bool(”text”)) True
print(bool(” ”)) False
print(bool(’ ’)) True
print(bool(0)) False
print(bool( )) False
print(bool(3)) True
print(bool(None)) False

12. 23 v 1.2
String
Type string, str , a sequence of characters
A single character is a string of length 1
Enclose in quotes single, double, even
triple!
>>> c i t y = ’ C hennai ’
>>> p r i n t ( t y p e ( c i t
y ) )
<c l a s s ’ s t r ’>
>>> c i t y = ” C hennai ”
>>> p r i n t ( t y p e ( c i t
y ) )
<c l a s s ’ s t r ’>
>>> d i a l og u e = ’ ’ ’ He s a i d
>>> p r i n t ( t y p e ( d i a l og u
e ) )
h i s f a v o u r i t e book is
h i nk Python ’ ’ ’
2
6
T,
<c l a s s ’ s t r
’>

13. String
>>> p r i n t ( t y p e ( ” 17 ” ) )
<c l a s s ’ s t r ’>
>>> p r i n t ( t y p e ( ” 3 . 2 ” ) )
<c l a s s ’ s t r ’>
>>> p r i n t ( t y p e ( ”” ” H ell o ”” ” ) )
<c l a s s ’ s t r ’>
Double quoted strings can contain single quotes inside them
Single quoted strings can have double quotes inside them
Triple quoted strings can even span multiple lines
13 v 1.2
broken !” ’ ’ ’ )
”Oh no” , sh
e
ex c l a im ed , ” B en ’ s b i k e i s b rok en !
”
r
no
ou c
”t i o
,P
sy
ht
h o
en
>>> p r i n t ( ’ ’ ’ ”Oh exc l aN
io
me m b
ee
d2 6 ,
, ” B e2n8 ’
s bi ke i s

14. Operations on Strings
14 v 1.2
Concatenate with + or neighbors
>>>x= ’ a
’
>>> word
>>> word
’ Helpa ’
= ’ Help ’ + x
s u b s c r i p t i n g of s t r i n g
s
>>>p r i n t ( word [ 2 ] )
>>>l
s l i c e :
>>>p r i n t ( word [ 0 : 2 ] )
>>> ’ he ’
>>>p r i n t ( word [ − 1 ])
>>>a
>>>p r i n t ( l en ( word ) )
>>> 5

15. List
15 v 1.2
• List is an ordered collection of values which can be of mixed type.
• Consist of items separated by commas enclosed within [ ].
• Values stored can be accessed using indexes
• Index of first element is 0 and last element is n-1 (n=length)
>>> f a c t o r s = [ 1 , 2 , 3 , 4 , 5 ]
>>> p r i n t ( t y p e ( f a c t o r s ) )
< c l a s s ’ l i s t ’>
>>> name= [” J oe” , ” Sam” , ” H a l e” ]
>>> p r i n t ( t y p e ( name) )
< c l a s s ’ l i s t ’>
>>> p r i n t ( name)
[ ’ Joe ’ , ’Sam ’ , ’ Hale ’ ]
>>> mix ed = [I n
3t
,d
Tu
rue , ’t
y ell ow ’ , 3e
. 5e r
]2 6 ,
>>> p r i n t ( mix ed )
[ 3 , T rue , ’ y ell ow ’ , 3 . 5 ]

16. Tuple
16 v 1.2
• Tuple is similar to list and consist of items separated by
commas enclosed within ( ) .
• List is mutable but Tuple is immutable.
>>> f a c t o r s = ( 1 , 2 , 3 , 4 , 5 )
>>> t y p e ( f a c t o r s )
< c l a s s ’ t u p l e’>
>>> name= ( ” J oe” , ” Sam” , ” H a l e” )
>>>p r i n t ( t y p e ( name) )
< c l a s s ’ t u p l e’>
>>> p r i n t ( name)
( ’ Joe ’ , ’Sam ’ , ’ Hale ’ )
>>> mixed =(3 , True , ’ yello wN ’ m, b3e .256 , )2 0 2 2
>>> print ( mixed ) ( 3 , True , ’ ye l low ’ ,
3.5)
>>> type ( mixed )
< c l ass ’ tuple ’>

17. Dictionary
Unordered collection of name-value pair or key-value pair and are
enclosed within { }.
Keys are strings and value can be any data type.
Specify the key in square braces [ ] to access any value.
person = { "name": "Alice", "age": 30, "city": "New
York"}
print(person["name"]) # Output: Alice
person["age"] = 31 #Modify
17 v 1.2

18. 29 v 1.2
Summar
y
• Python Data Types
– Numeric
– None
– Boolean
– String
– List
– Tuple
– Dictionary

19. 30 v 1.2
Check your
understanding
• Suppose a tuple test contains 5 elements. How can
you
set the 3rd element of the tuple to ‘Python’?
•Suppose a list with name test, contains 10 elements. You
can get the 5th element from the test list using ___.
• What is the output for:
>>> ” He l lo ” + ’ World ’ + ””” ! ”””

20. 31
Think Python 2nd Edition by Allen B. Downey.