Python

Introduction to Python
 Python is a simple programming language used to
write codes for the computer programs.
 Python was created by Guido Van Rossum when he
was working at CWI( Centrum Wiskunde &
Informatica), which is a National research institute
for mathematics and computer science in
Netherland.
 The language was release in 1991.
 Python is a high level programing language.
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FEATURES OF PYTHON
 It is an easy to learn general purpose programing
language.
 It is a platform independent programing language,
which means it can be used on any machine and in
any operating system.
 It has a simple syntax
 Python is a case sensitive language.
 It is an interrupted language.
 It is free to use and even free for commercial product.
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APPLICATIONS OF PYTHON
PROGRAMING
 Build a website
 Develop games
 Program robot
 Perform scientific computation
 Develop artificial intelligence application

WHY LEARN PYTHON
 It cuts development time with its simple to
read syntax and easy compilation features.
 Debugging your program is a breeze in python
with its built in debugger
 Python makes programmers more productive
 Python runs on windows Linux/Unix, Mac OS
and has been ported to JAVA and .NET virtual
machines.

Python has evolved as the most
preferred language for Data
Analytics and the increasing search
trends on Python also indicates that
Python is the next ‘Big Thing’ and
most for professionals in the Data
Analytics Domain.

Arithmetic Operators
Add two operands
>>2+3
5
Subtract two operands
>>5-1
4
Multiply two operands
>>2*3
6
Divide left operand with
right and result in float.
>>6/3
2.0
+
-
*
/

EXAMPLE
num1 = 30
num2 = 10
Print(“num1 + num2 =“, num1+num2)
Print(“num1 - num2 =“, num1-num2)
Print(“num1 * num2 =“, num1*num2)
Print(“num1 / num2 =“, num1/num2)
OUTPUT
num1+num2= 40
num1+num2= 20
num1+num2= 300
num1+num2= 3

Assignment Operators
>>x=5
/=
 x=x/ <right operand>
 >>x/=5
 >>print(x)
 1.0
%=
 x=x% <right operand>
 >>x%=5
 >>print(x)
 0
//=
 x=x// <right operand>
 >>x//=2
 >>print(x)
 2
**=
 x=x** <right operand>
 >>x**=5
 >>print(x)
 3125

Comparison Operators
>
 True if left operand is
greater than the right
 >>2 > 3
 False
<
 True if left operand is less
than the right
 >>2 < 3
 True
==
 True if left operand is
equal to right
 >>2 == 3
 False
!=
 True if left operand is not
equal to the right
 >> x!= 3
 True

Logical Operators
 And
 Returns x if x is False , y otherwise
 >> 2 and 3
 3
 or
 Returns y if x is False , x otherwise
 >> 2 or 3
 2
 not
 Returns True if x is True , False otherwise
 >> not 1
 False

Bitwise Operators
 a| b
 Perform OR operation on
each bit of the number
 111 7
 101 5
 111 7
 a & b
 Perform AND operation on
 111 7
 101 5
 101 5
 a ^ b
 Perform XOR operation on
 111 7
 101 5
 010 2
 a>>b
 shift a right by b bits
 3>>2 = 0
 0011 0000
 a<<b
 shift a left by b bits
 3<<2 = 12
 0011 1100

Identity Operators
 is
 True if the operands are identical (refer to the same
object)
 >> x = 5
 >> x is 5
 True
 is not
 True if the operands are not identical (do not refer to the
same object)
 >> x = 5
 >> x is not 5
 False

Membership Operators
 x = [ 1,2,3,4,5]
 In
 True if it finds elements in the specified sequence
 >> 3 in x
 True
 Not in
 True if it does not finds elements in the specified
sequence
 >> 3 not in x
 False

DATATYPE
 Python is a loosely typed language. Therefore, no need
to define the datatype of variables.
 No need to declare variables before using them.

Datatype
Immutable
NUMBERS
 Integer
 Float
 Complex
 Strings
 Tuples
Mutable
Lists
Dictionaries
Sets
 Integer
Example 1,4 etc
4+2=6
2**3=8
 Float
Example 1.4, 2.3 etc
4.0+2.5=6.5
6/2=3.0
 Complex
Example 1+4j etc
(3+4j)+(1+1j)=4+5j
(2+2j)*2=4+4j

Datatype
Immutable
 Numbers
 STRINGS
 Tuples
Mutable
Lists
Dictionaries
Sets
 Strings are sequence of one-
character strings
 Example:
1. Sample = “Welcome to python
Tutorial”
2. Sample = ‘Welcome to python
Tutorial’
 Multi-line strings can be denoted
using triple quotes, “’ or “””
 Example:
1. Sample = “”” It will help you lean
Python fundamentals with
examples in detail.”””

Sequence operations:
 Concatenation:
 ‘Python’ + ‘Tutorial’ ‘Python Tutorial’
 Repetition:
 ‘Stem’ * 2 ‘StemStem’
 Slicing:
 string1 = ‘Stem’ string1[2:4] ‘em’
 Indexing:
 string1 = ‘Stem’ string1[-1] +string[1] ‘ms’

 Find
 str = ‘Python’ str.find(‘on’) 4
 Replaced()
 str = ‘samee’ str.replace(‘ee’,’i’) ‘sami’
 Split()
 str = ‘S,A,M’ s.split(‘,’) [‘S’,’A’,’M’,]
 Count()
 str = ‘Python’ str.count(‘P’, beg=0,end=5) 1

 Upper():
 str = ‘Python’ str.upper() PYTHON
 max()
 str = ‘samee’ max(str) ‘s’
 min()
 str = ‘Python’ min(str) ‘P’
 isalpha()
 str = ‘Python’ str.isalpha() True

DATATYPE
Immutable
 Numbers
 Strings
 TUPLES
Mutable
Lists
Dictionaries
Sets
 A tupples is a sequence of
immutable Python objects like
floating number, string literals etc
 The tuples can’t be changed unlike
lists.
 Tuples are defined using curve
braces.

Sequence operation:
 Concatenation:
 tup = (‘a’ , ’b’ , ’c’) tup+(‘d’ , ‘f’) (‘a’ , ’b’ , ’c’ , d’ , ‘f’)
 Repetition:
 tup = (‘a’ , ’b’ , ’c’) tup*2 (‘a’ , ’b’ , ’c’, ‘a’ , ’b’ , ’c’)
 Slicing:
 tup = (‘a’ , ’b’ , ’c’) tup[1:2] (’b’ , ’c’)
 Indexing:
 tup = (‘a’ , ’b’ , ’c’) tup[0] ‘a’

DATATYPE
Immutable
 Numbers
 Strings
 Tuples
Mutable
 LISTS
 Dictionaries
 Sets
 A lists is a sequence of mutable
Python objects like floating
number, string literals, etc.
 The lists can be modified.
 Tuples are defined using square
braces.

Type Specific Method:
 Append(value)
 list = [1, ‘a’, 2.5] list.append(‘d’) [1 , ‘a’ , 2.5, ’d’]
 Extend(list)
 list = [1, ‘a’ ,2.5] list.extend ([‘c’ , ’d’]) [1, ’a’, 2.5, ’c’, ’d’]
 Insert(index , value)
 list = [1, ‘a’ ,2.5] list.insert(2,’b’) [1 , ‘a’ , ’b’, 2.5]
 Pop()
 list = [1, ‘a’ ,2.5] list.pop() [‘a’ , ’b’]

DATATYPE
 Immutable
 Numbers
 Strings
 Tuples
 Mutable
 Lists
 DICTIONARIES
 Sets
 Dictionaries are perhaps the
most flexible built-in data
type in python.
 Dictionaries, items are stored
and fetched by key, instead of
by positional offset.

Dictionary Examples
 Empty dictionary
 myDict={}
 Dictionary with integer keys
 myDict = {1:’apple’,2:’ball’}
 Dictionary with mixed keys
 myDict = {‘name’:’John’, 1:[2,4,3]}
 From sequence having each item as a pair
 myDict = dict([(1,’apple’),(2,’ball’)])

Dictionary Methods
 accessing dictionary
 myDict = {1:’apple’,2:’ball’} myDict[1] ‘apple’
 len()
 myDict={1:’apple’,2:’ball’} len{myDict} 2
 key()
 myDict={1:’apple’’,2:’ball’} myDict.key() [1,2]
 values()
 myDict={1:’apple’’,2:’ball’} myDict.values() [‘apple,’ball]
 items()
 myDict={1:’apple’’,2:’ball’} myDict.items() [(1,’apple’),(2,ball)]
 Get()
 myDict={1:’apple’’,2:’ball’} myDict.get(1) ‘apple’
 Update()
 myDict={1:’a’,2:’b’} myDict.update({3:’c’}) {1:’a’,2:’b’,3:’c’}
 Pop()
 myDict={1:’apple’’,2:’ball’} myDict.pop(2) {1:’apple’}

DATATYPE
Immutable
Numbers
Strings
Tuples
Mutable
Lists
Dictionaries
SETS
 A set is an unordered
collection of items.
 Every element is unique (no
duplicates) and must be
immutable (which cannot
be changed).

Sets method
 creating set
 mySet = {1,2,3,3} {1,2,3}
 union
myS1={1,2,’c’}
myS2={1,’b’,’c’} myS1| myS2 {1,2,’c’,’b’}
 intersection
myS1={1,2,’c’}
myS2={1,’b’,’c’} myS1 & myS2 {1,’c’}
 difference
myS1 = {1,2,’c’}
myS2={1,’b’,’c’} myS1-myS2 {2}

1. If statement
Syntax:
if(condition):
statement 1……
else:
statement2….
START
CHECK
CONDITION
EXECUTE
BLOCK1
EXECUTE
BLOCK2

START
CHECK
CONDITION1
EXECUTE
BLOCK1
EXECUTE
BLOCK2
CHECK
CONDITION2
EXECUTE
BLOCK3
Syntax:
if(condition1):
statement 1……
elif(condition2):
statement2….
else:
statement3….
2. if…elif…else statement

3. while statement
Syntax:
while(condition is true):
statement 1……
START
CHECK
CONDITION1
EXECUTE
BLOCK1
EXIT LOOP
REPEAT

4. For statement
Syntax:
for iterator name in iterating sequence:
Execute statements...
COUNT = 0
START
Execute Statements
Add 1 to Count
repeat
Check if
Count < 10 EXIT LOOP

5. Break statement
Syntax:
Break
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START
Check loop
Condition
Execute
Block
Check break
Condition
EXIT LOOP
EXIT LOOP
Repeat
50

6. Continue
Syntax:
continue
START
Check loop
Condition
Skip Next
Statement
Check continue
Condition
EXIT LOOP
Execute Block
Repeat

A function is a block of organized, reusable sets of instructions
that is used to perform some related actions.
 Why do we use functions?
 Re-usability of code minimizes redundancy
 Procedural decomposition makes things organized

USER DEFINED FUNCTION
 SYNTAX:
def func_name(arg1,arg2,arg3,…):
Statements…
return [expression]
 Example:
def add(a,b)
Sum = a+b
return sum

 Abs()
 The abs function returns the absolute value of the specified number.
 Syntax abs(x)
 Example x=abs(3+5j)
 All()

Python

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