Chapter 10 data handling

Unit 2:
Programming and Computational Thinking
XI
Computer Science (083)
Board : CBSE
Courtesy CBSE

Unit II
Computational Thinking and
Programming
(60 Theory + 45 Practical)
DCSc & Engg, PGDCA,ADCA,MCA.MSc(IT),Mtech(IT),MPhil (Comp. Sci)
Department of Computer Science, Sainik School Amaravathinagar
Cell No: 9431453730
Praveen M Jigajinni
Prepared by
Courtesy CBSE

INTRODUCTION
Data can be of many types e.g.
character, string, integer, real etc.
Python like any other language
provides ways and facilities to handle
different types of data by providing data
types.

PYTHON DATA TYPES
What is Data type?
DATA TYPES are means to identify
the type of data and associated
operations of handling it.

NUMBERS
The numbers can be represented in
the python as:
(i) Integers.
(ii) Floating point Numbers.
(iii) Complex Numbers.

(i) INTEGERS
Integers numbers are whole
numbers (without any fractional part).
For example: 123,-789 etc.

TYPES OF INTEGERS
There are two types of integers:
(i) Integers (Signed).
(ii) Booleans.
Signed
Integers
Booleans
Types
of
Integers

Integers can be of any length.
Its only limited by the memory
available.
It’s a signed representation,
i.e., the integers can be positive or
negative.
(i) INTEGERS (SIGNED)

(ii) BOOLEANS
Boolean data types are the
truth values, i.e., True form or False
form.
Boolean data type is a one kind of
integer type they can be represented in
the integer form i.e., 0 and 1.

(ii) BOOLEANS
practically one can execute as
>>>bool(0)
will give result as false
>>>bool(true)
will produce 1 result.

str ( ) Function
str ( ) function coverts a value to
string type.
>>>str(false)
will give string type result ‘false’
>>>str(true)
will produce string type ‘true’ result.

(ii) FLOATING POINT NUMBERS
A numbers containing
fractional part is called floating point
number.
for example: 93.452
Floating point numbers can be
written in two forms.
Note: Floating point numbers have
precision of 15 Digits( double precision)
in python.

(ii) FLOATING POINT NUMBERS
Floating
Point
Numbers
Fractional
Form
Exponent
Notation
Note: Floating point numbers have precision of
15 Digits( double precision) in python.

(ii) Advantages of Floating Point Numbers
1. They can represent range of values
between the integers.
2. They can represent a greater extent/
range of values.

Disadvantages of Floating
Point Numbers

(ii) Disadvantages of Floating Point Numbers
Floating-point operations are
usually slower than integer operations.

(iii) COMPLEX NUMBERS
A complex number is a number that
can be expressed in the form a + bi,
where,
a and b are real numbers, and
i is called an imaginary number.
For the complex number a + bi, a is
called the real part, and b is called
the imaginary part.

COMPLEX NUMBERS IN PYTHON
complex number is made up of real and
imaginary parts.
Real part is a float number, and imaginary
part is any float number multiplied by
square root of -1 which is defined as j.

>>> no=5+6j
>>> no.real o/p 5.0
>>> no.imag o/p 6.0
>>> type(no)
<class 'complex'>

Python library also has complex()
function, which forms object from two
float arguments
>>> no=complex(5,6)
>>> no (5+6j)
>>> no.real o/p 5.0
>>> no.imag o/p 6.0
>>> type(no)
<class 'complex'>

Data Type Range
Data Type Range
Integers Unlimited subject to
availability of memory
Booleans True ( 1 ), False ( 0 )
Floating Point
Numbers
Unlimited subject to
availability of memory
and depends on machine
architecture.
Complex Numbers Same as float type

What is UNICODE?
Unicode provides a unique
number for every character,
no matter what the platform,
no matter what the program,
no matter what the language.

The origins of Unicode date to
1987, when Joe Becker from Xerox with Lee
Collins and Mark Davis from Apple, started
investigating the practicalities of creating a
universal character set.
UNICODE HISTORY

With additional input from Peter
Fenwick and Dave Opstad, Joe Becker
published a draft proposal for an
"international/multilingual text character
encoding system in August 1988,
tentatively called Unicode". He explained
that the name 'Unicode' is intended to
suggest a unique, unified, universal
encoding".
UNICODE HISTORY

It has been adopted by all
modern software providers and now allows
data to be transported through many
different platforms, devices and
applications without corruption.
operating systems, search engines,
browsers, laptops, and smart phones—plus
the Internet and World Wide Web (URLs,
HTML, XML, CSS, JSON, etc.) using unicode
UNICODE ADOPTION

Unicode can be
implemented by different character
encodings. The Unicode standard
defines UTF-8, UTF-16, and UTF-32, and
several other encodings are in use. The
most commonly used encodings are UTF-8,
UTF-16 and UCS-2, a precursor of UTF-16.
UNICODE IMPLIMENTATION

Like many other popular
programming languages, strings in
Python are arrays of bytes representing
Unicode characters. However, Python does
not have a character data type, a single
character is simply a string with a length of
1. Square brackets can be used to access
elements of the string.
STRINGS

How to create a string in Python?

How to create a string in Python?
Strings can be created by enclosing
characters inside a single quote or double
quotes. Even triple quotes can be used in
Python but generally used to represent
multiline strings and docstrings.
STRINGS

REPRESENTATION OF STRING
>>> s = “Hello Python”
This is how Python would index the string:
Forward Indexing
Backward Indexing

STRINGS – Programming Example

STRINGS - Example
Output Next Slide...

How to access characters in a string?

We can access individual characters
using indexing and a range of characters
using slicing. Index starts from 0. Trying to
access a character out of index range will
raise an IndexError. The index must be an
integer. We can't use float or other types,
this will result into TypeError.
STRINGS

Python allows negative indexing for
its sequences.
The index of -1 refers to the last item,
-2 to the second last item and so on. We
can access a range of items in a string by
using the slicing operator (colon).
STRINGS

SLICING STRINGS EXAMPLES
For example:
>>>“Program”[3:5]
will result in:
‘gr ’
>>>“Program”[3:6]
will yield:
‘gra’
>>>p = “Program”
>>>p [4:]
‘ram’
>>>p [3:6]
‘gra’

SLICING STRINGS EXAMPLES
For example:
>>>p [:4]
‘Prog’

MUTABLE AND IMMUTABLE OBJECTS
IN PYTHON

What is Mutable Object?
In object-oriented programming
language , an immutable object is an object
whose state/ values can be modified after its
creation.
In short the an object / variable, for
which we can change the value is
called mutable object or mutable variable.
For example : Lists are mutable in nature.

What is Immutable Object?
In object-oriented programming
language, an immutable object is an object
whose state/ values can not be modified after
it’s creation.
In short an object or a variable , for
which we can not change the value
is immutable object or immutable variable.
For example : Tupels are immutable in nature.

TUPLES
What is Tuples?
Lists and tuples can be thought of as
generic "buckets" with which to hold an
arbitrary number of arbitrary Python objects.

TUPLES
What is Tuples or Tuple?
Tuples are the type of data it is a sequence
of immutable Python objects. Tuples are
sequences, just like lists. The differences
between tuples and lists are, the tuples cannot
be changed unlike lists and tuples use
parentheses, whereas lists use square brackets.
Creating a tuple is as simple as putting different
comma-separated values

TUPLES EXAMPLE
DEFINING TUPLES WITHOUT ( )

TUPLES EXAMPLE
DEFINING TUPLES WITH ( )

TUPLES EXAMPLE – Accessing individual
elements using index number in [ ]

A list is a data type that can be used to store
any type and number of variables and information.
Lists are mutable in nature.
General format of list is :
my_list = [item_1, item_2, item_3]
Python also allows creation of an empty list:
my_list = []
For Example
colors = ["Orange" , "red" , "Green" , "White“]
LISTS

LISTS
Note: Lists are mutable in nature.

PRECEDENCE OF AN OPERATOR
Operator Description
** Exponentiation (raise to the
power)
~ + - Complement, unary plus and
minus (method names for the last
two are +@ and -@)
* / % // Multiply, divide, modulo and floor
division

+ - Addition and subtraction
>> << Right and left bitwise shift
& Bitwise 'AND'td>
^ | Bitwise exclusive `OR' and regular
`OR'
<= < > >= Comparison operators
<> == != Equality operators

= %= /= //=
-= += *=
**=
Assignment operators
is is not Identity operators
in not in Membership operators
not or and Logical operators

EXAMPLE ON

PRECEDENCE OF OPERATOR EXAMPLE

CLASS TEST
ON
DATA TYPES
CHAPTER

CLASS TEST ON DATA TYPES
Each carries 2 Marks Questions (10 x 2 = 20)
1. What is DATA TYPE?
2. What is tuple/ are tuples? Give syntax or
general format and one suitable example.
3. What is mutable object?
4. What is list/ are lists? Give syntax/general
format and support with one example
5. What is str ( ) function?
6. What are the advantages of floating point
numbers?
7. Write down the syntax of complex numbers
and give one example.

Each carries 2 Marks Questions (10 x 2 = 20)
7. What is an index error?
8. Explain the string representation with
proper diagram.
9. What is forward indexing and backward
indexing.
10. How to access a specific character from a
given string.
***
CLASS TEST ON DATA TYPES

QUESTION BANK
ON
CHAPTER III
DATA HANDLING

1. What is DATA TYPE?
2. List the Data types?
3. How many ways numbers can be represented
in python language?
4. Name the types of Integers?
5. What is str ( ) function?
6. What are the advantages of floating point
numbers?
7. Write down the syntax of complex numbers and
give one example.
CHAPTER 2: PYTHON FUNDAMENTALS
One Mark Questions

8. What is index error?
9. Explain the representation of string with
proper diagram.
10. What is forward indexing and backward
indexing?
11. How to access a specific character from a
given string.
12. What is tuple?
One Mark Questions

1. Write down the syntax of tuple without
braces and give one example.
2. Write down the syntax of tuple with braces
and give one example.
3. What is index? Give example
4. What is index number? Give example
5. How an element of tuple/tuples are
accessed? Explain with proper example.
6. Differentiate between mutable and
immutable objects.
Two Marks Questions

7. Differentiate between lists and tuples?
Give suitable example.
Two Marks Questions

Three Marks Questions
1. What are the python naming conventions?
2. Explain the representation of string in python
language.
3. Explain the types of strings supported by
python language.
4. Explain escape sequences.
5. Explain numerical literals supported in python
language.
6. Explain the Floating point literals supported in
python language.

Chapter 10 data handling

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