Python-03| Data types

What are data types?
O A data type is a classification of data which tells
the compiler or interpreter how the programmer
intends to use the data.
O Every value in Python has a data type. Since
everything is an object in Python programming,
data types are actually classes and variables are
instance (object) of these classes.

Python allows several data types
O Int
O Float
O Complex
O bool
O Strings
O Bytes
O Byte array
O List
O Tuple
O range
O Set
O Frozen set
O Dictionary
O None

Data Types
SetsNumeric Sequence Mapping
int float Complex
bool
Str Bytes Byte array List Tuple
Set Frozen set
Dictionary
Python's data types can be grouped
into several classes
Range

Fundamental data Types
O The first five data types i.e., int, float, complex,
bool and str are in-built data types or standard
data types.
O All fundamental data types are immutable.
O Immutable means can’t modify.
O Mutable means can be modified.

Integer data type
O To hold integral values i.e., whole number
e.g., 123, 435.
O 4 ways to represent
O Decimal form (x = 10)
O Binary form (x = 0b10)
O Octal form (x = 0o75)
O Hexadecimal form (x = 4F)

Example
Python provide output in the decimal form.
What if we want output in binary or octal or hex?

Base conversion
O Some built-in function are used
O bin(x)
O Oct(x)
O Hex(x)
Decimal, octal, hex
e.g. bin(15) = 1111
Decimal, binary, hex
Decimal, binary, octal
e.g. hex(10) = 0xa

Floating data type
O E.g., 123.456
O There is no way to specify float value in
binary, octal or hexadecimal.
O a = 0x123.45 will through an error

Cont....
Exponential form
f = 1.2e3
It means 1.2 * 10^3 = 1.2 *1000 = 1200

Complex data type
O Format is a + bj
a is called real part
b is called imaginary part
j² = -1
O Use to develop mathematical application or
scientific application.
O 10 + 20j
Only j is valid
10 + 29i will through error

Cont...
a + bj
Real value
Can be int, float
Can only be in decimal form
2, 2.3
binary octal Hexa decimal

Operation on complex
Real/imag are not function
they are in built attributes to
get real or imaginary value

Bool data type
O To represent logical values.
O Allowed values of Bool data types
O True
O False Compulsorily ‘T’ & ‘F’ are capital

True = 1 & False = 0
True & False are resented as 1 & 0
respectively

Str data type
O Any sequence of character known as string.
O Enclosed in quotes of any type --- single
quotation, double quotation and triple
quotation (for multiple lines).
O Python strings are immutable(will be
discussed).

Should be in quotes
Output in single quote only, even
when input is given in double quote
Triple quote for multiline
In shell it shows n as line break

Bytes data type
O Represent a group of byte numbers just like an array.
O Every value should be in the range of 0 to 256
O Bytes data type is immutable.

Bytearray data type
O Same as bytes data type, the only difference is
bytearray is mutable
immutable
mutable

List data type
O Represents a group of comma-separated values of any
data type between square brackets.
O Duplication is allowed.
O Lists are mutable i.e., they can be modified.

Tuples data type
O Tuples are represented as group of comma-separated
values of any data type within parenthesis.
O Tuples are same as lists but tuples are immutable.
Accessing element
Modification is not allowed since tuples are immutable

Range data type
O Represent a sequence of values.
O Immutable
O Can be represented by different forms
O Form-1 → with one argument
O E.g.: range(x)→represent values from 0 to (x-1)
O Always Starts from 0
O Form-2 → with two argument
O E.g.: range(x, y)→represent values from x to (y-1)
O Starts from x.
O Form-3 → with three argument
O E.g.: range(x, y, z)→represent values from x to (y-1) with
difference of z. Technically word for z is step.
x, y, z that is argument of range always be in integral value

Form-1 [with one argument]
Modification is not allowed (immutable)

Set data type
O Difference between list and set
O In list the order is preserved (important) and duplication is
allowed.
O In sets, it don’t worry about order and don’t allow duplicate
O Set is an unordered collection of unique items. Set is
defined by values separated by comma inside braces { }.
Items in a set are not ordered.
O Sets are mutable (i.e., modifiable)
O Heterogeneous objects are allowed

• Indexing or slice operator is not allowed since there is no
guarantee in sets that which element is at first position or
which at second bcuz order is not preserved

frozenset data type
O Exactly same as set data type except it is
immutable

dict data type
O Till yet we have studied about
bytes, bytearray, list, tuple, set, frozenset, range
A group of individual elements/objects, there is
no relation between them.
List, set etc....
Individual objects
What if I want some relation between objects like
Roll no → name (relation between roll no. and name of stu.)
Word → meaning (relation between word and its meaning)

Cont...
O Dictionary is collection of entries in which each entry contains a
key and a corresponding value.
O Duplication is keys are not allowed but values can be duplicate
O Represented as d = {100: ‘john’, 200: ‘smith’}
O Key and values can be heterogeneous
O d = { } #an empty dictionary then what about empty set?
O Empty set can be represented as: s = set()
100 John
200 smith
Key Value
key value

Adding elements to dictionary
O Dictionary is mutable so we can allowed to add or remove objects.
Old value(john) replaced by new value

None data type
O None means nothing or no value associated.

Data type
Immutable Mutable
Numbers Strings Tuples
List Set Dictionary
Python data type classified into:

Class Immutable? Mutable?
Int 
Float 
Complex 
Bool 
Str 
Bytes 
Bytearray 
Range 
List 
Tuple 
Set 
Frozenset 
Dictionary 

Python-03| Data types

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