For polytechnic college lectures

1. PYTHON PROGRAMMING
RIYAZ P A
Email : riyazaahil@gmail.com

2. TODAY’S CLASS
• Introduction
• What is Python ?
• Why Python ?
• Features
• Basics of Python
• Syntax
• Import
• Input Functions
• Output Functions
PYTHON PROGRAMMING 2

3. WHAT IS PYTHON ?
PYTHON PROGRAMMING 3
 Python is a widely used general-purpose, high-level programming
language.
 Python is simple and powerful language

4. WHY PYTHON ?
PYTHON PROGRAMMING 4

5. WHY PYTHON ?
PYTHON PROGRAMMING 5
Ease of Use and Powerful
Community Driven
Currently it’s in the top five programming languages in the
world according to TIOBE Index
Two times winner of Programming Language of the
Year(2007 and 2010) by TIOBE Index

6. FEATURES
PYTHON PROGRAMMING 6
 Simple
 Free and Open Source
 Powerful
 Object Oriented
 Dynamic, strongly typed scripting language
 Portable
 Interpreted

7. FEATURES
PYTHON PROGRAMMING 7
 Embeddable
 Extensive Libraries
 Scalable
Extensible

8. CAN DO
 Text Handling
 System Administration
 GUI programming
 Web Applications
 DatabaseApps
 Scientific Applications
 Games
 NLP
 ImageProcessing
 IoT and lot more …..
PYTHON PROGRAMMING 8

9. ZEN OF PYTHON
PYTHON PROGRAMMING 9

10. PYTHON PROGRAMMING 10

11. WHO USES PYTHON ?
PYTHON PROGRAMMING 11

12. RELEASES
PYTHON PROGRAMMING 12
 Createdin 1989 by Guido Van Rossum
 Python 1.0 releasedin 1994
 Python 2.0 releasedin 2000
 Python 3.0 releasedin 2008
 Python 2.7 is the recommendedversion
 3.0 adoption will take a fewyears

13. HELLO WORLD
hello_world.py
print('Hello, World!')
PYTHON PROGRAMMING 13

14. PYTHON 2 vs PYTHON 3
 print ('Python‘)
print 'Hello, World!'
 print('Hello, World!')
 In python 3 second statementwill show an error
File "", line 1
 print 'Hello, World!'
 ^
SyntaxError: invalid syntax
PYTHON PROGRAMMING 14

15. SAVING PYTHON PROGRAMS

PYTHON PROGRAMMING 15

16. COMMENTS
#Hello
‘’’ Hai
hello
‘’’
PYTHON PROGRAMMING 16

17. IMPORT
 When our program grows bigger, it is a good idea to break it into
different modules.
A module is a file containing Python definitions and statements.
 Python modules have a filename and end with the extension .py
 Definitions inside a module can be imported to another module
or the interactive interpreter in Python.
 . We use the import keyword to do this.
PYTHON PROGRAMMING 17

18. IMPORT
>>> import math
>>> math.pi
3.141592653589793
>>> from math import pi
>>> pi
3.141592653589793
PYTHON PROGRAMMING 18

19. IMPORT
 While importing a module, Python looks at several places defined in
sys.path.
 It is a list of directory locations.
 >>> import sys
>>> sys.path
['',
 'C:Python33Libidlelib',
 'C:Windowssystem32python33.zip',
 'C:Python33DLLs',
 'C:Python33lib',
 'C:Python33',
 'C:Python33libsite-packages']
PYTHON PROGRAMMING 19

20. SUM OF TWO NUMBERS
# Store input numbers
num1 = input('Enter first number: ') # input is built-in function
num2 = input('Enter second number: ') # input returns string
# Add two numbers
sum = float(num1) + float(num2)
# Display the sum
print('The sum of {0} and {1} is {2}'.format(num1, num2, sum))
PYTHON PROGRAMMING 20

21. FOR PYTHON 2
 from __future__ import print_function
 Type this in first line to avoid errors if you use python 2.
PYTHON PROGRAMMING 21

22. OUTPUT
>>> print('This sentence is output to the screen')
This sentence is output to the screen
>>> a = 5
>>> print('The value of a is',a)
The value of a is 5
PYTHON PROGRAMMING 22

23. OUTPUT…
For Python 3
print(1,2,3,4)
print(1,2,3,4,sep='*')
print(1,2,3,4,sep='#',end='&')
Output
1 2 3 4
1*2*3*4
1#2#3#4&
PYTHON PROGRAMMING 23

24. OUTPUT FORMATTING
 Sometimes we would like to format our output to make it look
attractive.
This can be done by using the str.format() method.
 This method is visible to any string object
>>> x = 5; y = 10
>>> print('The value of x is {} and y is {}'.format(x,y))
The value of x is 5 and y is 10
PYTHON PROGRAMMING 24

25. OUTPUT FORMATTING
>>> print('I love {0} and {1}'.format('bread','butter'))
I love bread and butter
>>> print('I love {1} and {0}'.format('bread','butter'))
I love butter and bread
>>> print('Hello {name},
{greeting}'.format(greeting='Goodmorning',name='John'))
Hello John, Goodmorning
PYTHON PROGRAMMING 25

26. OUTPUT FORMATTING
We can even format strings like the old printf() style used in C
programming language.
>>> x = 12.3456789
>>> print('The value of x is %3.2f' %x)
The value of x is 12.35
>>> print('The value of x is %3.4f' %x)
The value of x is 12.3457
PYTHON PROGRAMMING 26

27. AREA OF TRIANGLE
a = float(input('Enter first side: '))
b = float(input('Enter second side: '))
c = float(input('Enter third side: '))
# calculate the semi-perimeter
s = (a + b + c) / 2
# calculate the area
area = (s*(s-a)*(s-b)*(s-c)) ** 0.5
print('The area of the triangle is %0.2f' %area)
PYTHON PROGRAMMING 27

28. INPUT
Python 3
Syntax
input([prompt])
>>> num = input('Enter a number: ')
Enter a number: 10
>>> num
'10'
PYTHON PROGRAMMING 28

29. INPUT
Here, we can see that the entered value 10 is a string, not a number.
To convert this into a number we can use int() or float() functions.
>>> int('10')
10
>>> float('10')
10.0
PYTHON PROGRAMMING 29

30. INPUT EVAL
>>> int('2+3')
Traceback (most recent call last):
File "<string>", line 301, in runcode
File "<interactive input>", line 1, in <module>
ValueError: invalid literal for int() with base 10: '2+3'
>>> eval('2+3')
5
PYTHON PROGRAMMING 30

31. TEMPERATURE CONVERSION
# take input from the user
celsius = float(input('Enter degree Celsius: '))
# calculate fahrenheit
fahrenheit = (celsius * 1.8) + 32
print('%0.1f degree Celsius is equal to %0.1f degree Fahrenheit'
%(celsius,fahrenheit))
PYTHON PROGRAMMING 31

32. AVERAGE OF THREE NUMBERS
PYTHON PROGRAMMING 32
n1=float(input('1st num'))
n2=float(input('2nd num'))
n3=float(input('3rd num'))
avg=(n1+n2+n3)/3
print "Avarage os 3 numbers
{},{},{},={}n".format(n1,n2,n3,avg)
print ("Avarage os 3 numbers %0.2f %0.2f %0.2f%0.2f"
%(n1,n2,n3,avg))

33. KEYWORDS
PYTHON PROGRAMMING 33

34. DATA TYPES
 Strings
 Numbers
 Null
 Lists
 Dictionaries
 Booleans
PYTHON PROGRAMMING 34

35. Strings
PYTHON PROGRAMMING 35

36. Numbers
PYTHON PROGRAMMING 36

37. Null
PYTHON PROGRAMMING 37

38. Lists
PYTHON PROGRAMMING 38

39. Lists
PYTHON PROGRAMMING 39

40. Dictionaries
PYTHON PROGRAMMING 40

41. Dictionary Methods
PYTHON PROGRAMMING 41

42. Booleans
PYTHON PROGRAMMING 42

43. SQUARE ROOT
# Python Program to calculate the square root
num = float(input('Enter a number: '))
num_sqrt = num ** 0.5
print('The square root of %0.3f is %0.3f'%(num ,num_sqrt))
PYTHON PROGRAMMING 43

44. SQUARE ROOT - COMPLEX
# Find square root of real or complex numbers
# Import the complex math module
import cmath
num = eval(input('Enter a number: '))
num_sqrt = cmath.sqrt(num)
print('The square root of {0} is {1:0.3f}+{2:0.3f}j'.format(num
,num_sqrt.real,num_sqrt.imag))
PYTHON PROGRAMMING 44

45. OPERATORS
 Arithmetic
 String Manipulation
 Logical Comparison
 Identity Comparison
 Arithmetic Comparison
PYTHON PROGRAMMING 45

46. Arithmetic
PYTHON PROGRAMMING 46

47. String Manipulation
PYTHON PROGRAMMING 47

48. Logical Comparison
PYTHON PROGRAMMING 48

49. Identity Comparison
PYTHON PROGRAMMING 49

50. Arithmetic Comparison
PYTHON PROGRAMMING 50

51. VOLUME OF CYLINDER
PYTHON PROGRAMMING 51
from math import pi
r=input("Enter Radius")
h=input("Enter Height")
vol=pi*r**2*h
print (vol)

52. PYTHON PROGRAMMING 52

53. PYTHON PROGRAMMING 53

54. PYTHON PROGRAMMING 54

55. PYTHON PROGRAMMING 55

56. Avoid next line in print
Python 2.x
Print ”hai”,
Print ”hello”
Python 3.x
Print (‘hai’, end=‘’)
Print(‘hello’)
PYTHON PROGRAMMING 56

57. TODAY’S CLASS
• Intendation
• Decision Making
• Control Statements
PYTHON PROGRAMMING 57

58. INDENTATION
 Most languages don’t care about indentation
 Most humans do
 Python tend to group similar things together
PYTHON PROGRAMMING 58

59. INDENTATION
The else here actually belongs to the 2nd if statement
PYTHON PROGRAMMING 59

60. INDENTATION
The else here actually belongs to the 2nd if statement
PYTHON PROGRAMMING 60

61. INDENTATION
I knew a coder like this
PYTHON PROGRAMMING 61

62. INDENTATION
You should always be explicit
PYTHON PROGRAMMING 62

63. INDENTATION
Python embraces indentation
PYTHON PROGRAMMING 63

64. DECISION MAKING
 Decision making is anticipation of conditions occurring while execution
of the program and specifying actions taken according to the conditions.
Decision structures evaluate multiple expressions which produce TRUE
or FALSE as outcome.
You need to determine which action to take and which statements to
execute if outcome is TRUE or FALSE otherwise.
assumes any non-zero and non-null values as TRUE, and if it is either
zero or null, then it is assumed as FALSE value.
PYTHON PROGRAMMING 64

65. DECISION MAKING
PYTHON PROGRAMMING 65

66. DECISION STATEMENTS
 If
 If Else
 If Elif
 Nested If
PYTHON PROGRAMMING 66

67. IF
PYTHON PROGRAMMING 67
var1=100
if True:
print ("1 - Got a true“)
print (var1)
var2=0
if var2:
print ("2- Got a true“)
print (var2)
print ("good bye“)

68. IF ELSE : ODD OR EVEN
PYTHON PROGRAMMING 68
num=input("number")
if num%2==0:
print (num,'is Even‘)
else:
print (num,'is Odd‘)

69. IF ELIF
PYTHON PROGRAMMING 69
num=input("Enter a number")
if num>0:
print (num,'is Positive‘)
elif num==0:
print (num,'is Zero‘)
else:
print (num,'is Negative‘)
print ('Have a nice day‘)

70. NESTED IF
PYTHON PROGRAMMING 70
num=input("Enter a number")
if num>0:
print (num,'is Positive')
else:
if num==0:
print (num,'is Zero')
else:
print (num,'is Negative')
print ('Have a nice day')

71. LARGEST OF THREE NUMBERS
PYTHON PROGRAMMING 71
a=input('1st number')
b=input('2nd number')
c=input('3rd number')
if (a>b) and (a>c):
large=a
elif (b>a) and (b>c):
large=b
else:
large=c
print ('The largest number is ',large)

72. QUADRATIC EQUATION
PYTHON PROGRAMMING 72
import cmath
print 'Enter the Coeifficents'
a=input("a")
b=input("b")
c=input("c")
delta=(b**2)-4*a*c
if delta>0:
sq=delta**0.5
x=(-b+sq)/(2.0*a)
y=(-b-sq)/(2.0*a)
print 'roots are n {} n {}'.format(x,y)
#Cont to next slide

73. QUADRATIC EQUATION …
elif delta==0:
x=-b/(2.0*a)
y=x
print 'roots are Equal'
print 'roots aren {} n {}'.format(x,y)
else:
print 'imaginary'
#delta=-delta
sqi=cmath.sqrt(delta)
x=-b/(2.0*a)
#print x
print 'roots are n {0} + {1} j n {0} - {1} j
'.format(x,sqi.imag)
#print sqi.imag
PYTHON PROGRAMMING 73

74. LOOPS
 For
 While
 While else
 While Infinite Loop
 While with condition at top, middle and bottom
PYTHON PROGRAMMING 74

75. FOR
PYTHON PROGRAMMING 75
sum=0
for i in range(11):
print i
sum+=i
print ('sum=',sum)

76. FOR
PYTHON PROGRAMMING 76
start=input('Enter start')
stop=input('stop')
stepindex=input('step')
for i in range(start,stop+1,stepindex):
print (i)

77. NUMBERS DIV BY 7 and 2
PYTHON PROGRAMMING 77
num=[]
for i in range(100,1000):
if i%7==0:
num.append(i)
print (num)
print ('nnn')
num2=[]
for i in num:
if i%2==0:
num2.append(i)
print (num2)

78. FACTORIAL
PYTHON PROGRAMMING 78
num=input('Enter number')
f=1
if num==0:
print (f)
else:
for i in range(1,num+1):
#f*=i
f=f*i
print (f)

79. PRIME NUMBER
PYTHON PROGRAMMING 79
num=input('Enter number')
f=0
for i in range(2,(num/2)+1):
if num%i==0:
#print i
f=1
break
if f:
print (num,'is Not a Prime number‘)
else:
print (num,'is Prime number‘)

80. CONTINUE
PYTHON PROGRAMMING 80
num=[]
for i in range(100,1000):
if i%7==0:
continue
num.append(i)
print (num)

81. PASS
PYTHON PROGRAMMING 81
num=[]
for i in range(100,1000):
pass
For empty for loop, function and class , you need to use pass

82. WHILE LOOP
PYTHON PROGRAMMING 82
n=input('Enter a Number n')
sum=0
i=1
while i<= n:
sum+=i
i+=1
print ('The Sum is ',sum)

83. WHILE ELSE
PYTHON PROGRAMMING 83
count=0
while count<3:
print 'inside loop'
count+=1
else:
print 'outside loop'

84. INFINITE LOOP
PYTHON PROGRAMMING 84
i=1 # Use Ctrl+C to exit the loop.
#Do it carefully
while True:
print i
i=i+1

85. VOWEL
PYTHON PROGRAMMING 85
vowels="aeiouAEIOU"
while True:
v=input("Enter a Char: ")
if v in vowels:
break
print ('not a vowel try again')
print ('thank you')

86. MULTIPLICATION TABLE
PYTHON PROGRAMMING 86
num=input('Enter Number: ')
i=1
while i<11:
print ('{} * {} = {}'.format(i,num,num*i))
i+=1

87. MULTIPLICATION TABLE
PYTHON PROGRAMMING 87
num=input('Enter Number: ')
for i in range(1,21):
print ('{} * {} = {}'.format(i,num,num*i))

88. LCM
PYTHON PROGRAMMING 88
n1=input('Enter 1st number ')
n2=input('Enter 2nd number ')
'''
if n1>n2:
lcm=n1
else:
lcm=n2
'''
lcm=max(n1,n2)
while True:
if (lcm%n1==0) and (lcm%n2==0):
break
lcm+=1
print ('LCM of {} and {} is {}'.format(n1,n2,lcm))

89. STUDENT GRADE
PYTHON PROGRAMMING 89
name=raw_input('Enter Student Name: ')
gpa=input('Enter GPA: ')
if gpa>=9:
print ('{} has got {} Grade'.format(name,'S'))
elif gpa>=8 and gpa<9 :
print ('{} has got {} Grade'.format(name,'A'))
elif gpa>=7 and gpa <8 :
print ('{} has got {} Grade'.format(name,'B'))
elif gpa>=6 and gpa<7:
print ('{} has got {} Grade'.format(name,'C'))
elif gpa>=5 and gpa<6:
print ('{} has got {} Grade'.format(name,'D'))
else:
print ('{} is Failed'.format(name))

90. DAYS WITH FUNCTION
PYTHON PROGRAMMING 90
days={
1:'Sun',
2:'Mon',
3:'Tue',
4:'Wed',
5:'Thu',
6:'Fri',
7:'Sat'
}
def day(d):
if days.get(d):
print ('Day is ',days.get(d))
else:
print ('Invalid Key ‘)
d=input('Enter the Day: ')
day(d)

91. SUM OF DIGITS
PYTHON PROGRAMMING 91
n=input('Enter the Number: ')
s=0
while n>0:
# a=n%10
# print a
s+=n%10
n/=10
print ('Sum of digit is ',s)

92. PALINDROME NUMBER
PYTHON PROGRAMMING 92
n=input('Enter the Number: ')
rev=0
n1=n
while n>0:
rev=rev*10+n%10
n/=10
print ('Reverse of Number is ',rev)
if rev==n1:
print ('Palindrome‘)
else:
print ('Not Palindrome‘)

93. ANTIGRAVITY
Import antigravity
PYTHON PROGRAMMING 93

94. TODAY’S CLASS
• Functions
• Namespace
• Name Binding
• Modules
• Packages
PYTHON PROGRAMMING 94

95. TARGET SCENARIO
PYTHON PROGRAMMING 95

96. BUILDING BLOCKS
PYTHON PROGRAMMING 96

97. DIVISION OF LABOUR
PYTHON PROGRAMMING 97

98. DIVISION OF LABOUR
PYTHON PROGRAMMING 98

99. ASSEMBLY LINE
PYTHON PROGRAMMING 99

100. DIVIDE AND CONQUER
PYTHON PROGRAMMING 100

101. DIVIDE AND CONQUER
every problem can be broken down into smaller/more manageablesub-
problems
most computer programs that solve real-world problems are
complex/large
the best way to develop and maintain a large program is to construct it
from smaller pieces or components
PYTHON PROGRAMMING 101

102. PYTHON PROGRAM
COMPONENTS
 functions
classes
modules
 collectionof functions& classes
packages
 collectionof modules
PYTHON PROGRAMMING 102

103. PYTHON PROGRAM
COMPONENTS
PYTHON PROGRAMMING 103
Package
Module
Function
Class

104. FUNCTIONS
collection or block of statements that you can execute
whenever and wherever you want in the program
PYTHON PROGRAMMING 104

105. FUNCTIONS
PYTHON PROGRAMMING 105

106. FUNCTIONS
PYTHON PROGRAMMING 106

107. WHY FUNCTIONS
 avoids duplicating code snippets
 saves typing
 easier to change the program later
PYTHON PROGRAMMING 107

108. FUNCTIONS
def function_name(parameters):
"""docstring"""
statement(s)
PYTHON PROGRAMMING 108

109. USER DEFINED FUNCTIONS
PYTHON PROGRAMMING 109

110. USER DEFINED FUNCTIONS
PYTHON PROGRAMMING 110

111. RETURN KEYWORD
PYTHON PROGRAMMING 111

112. VARIABLE SCOPE
PYTHON PROGRAMMING 112
x = “Rahul”
def kerala():
x =“Suresh”
print (x)
kerala()
print x

113. PYTHON FUNCTIONS (PARAMS vs
ARGS)

PYTHON PROGRAMMING 113
Function Parameters
Function Arguments

114. PYTHON FUNCTIONS
(ARGUMENTS)
 You can call a function by using the following types of formal
arguments:
 Required Arguments
 Default Arguments
 Keyword Arguments
 Variable-Length Arguments
PYTHON PROGRAMMING 114

115. REQUIRED ARGUMENTS

PYTHON PROGRAMMING 115
Required/MandatoryArguments passed to a function in correct positionalorder
def sum(x,y):
return x+y
print sum(2, 3)

116. DEFAULT ARGUMENTS

PYTHON PROGRAMMING 116
assumes a default value if a value is not provided in the function call for
that argument.
def sum(x=1,y=1):
return x+y
print sum()
print sum(2, 3)
print sum(x=2)
print sum(x=2, y=3)
print sum(y=3, x=2)

117. KEYWORD ARGUMENTS

PYTHON PROGRAMMING 117
the caller identifies the arguments by the parameter name as keywords,
with/without regard to positional order
def sum(x,y):
return x+y
print sum(y=3, x=2)

118. VARIABLE ARGUMENTS

PYTHON PROGRAMMING 118
can handleno-argument, 1-argument, or many-argumentsfunction calls
def sum(*addends):
total=0
for i in addends:
total+=i
return total
print sum()
print sum(2)
print sum(2,3)
print sum(2,3,4)

119. TRY IT OUT
 Program to find the sum of digits
PYTHON PROGRAMMING 119

120. FIBONACCI
# Fibonacci numbers module
def fib(n): # write Fibonacci series up to n
a, b = 0, 1
while b < n:
print b,
a, b = b, a+b
def fib2(n): # return Fibonacci series up to n
result = []
a, b = 0, 1
while b < n:
result.append(b)
a, b = b, a+b
return result
PYTHON PROGRAMMING 120

121. SUM_AB FUNCTION
PYTHON PROGRAMMING 121
def sumab(a,b):
sum=0
for i in range(a,b+1):
sum=sum+i
return sum

122. MATRIX
PYTHON PROGRAMMING 122
# Read the Matrix
def readmat(r,c):
mat=[]
for i in range(r):
temp=[]
for j in range(c):
n=input('Enter the Number: ')
temp.append(n)
mat.append(temp)
return mat
# Calculate the sum
def matsum(r,c,a,b):
res=[]
for i in range(r):
temp=[]
for j in range(c):
sum=a[i][j]+b[i][j]
# print sum
temp.append(sum)
res.append(temp)
# print res
return res

123. MATRIX…
# Print Matrix
def printmat(r,c,a):
print 'The Matrix is n '
for i in range(r):
for j in range(c):
print a[i][j],"t",
print 'n '
print "nn"
# Find Transponse
def transpose(r,c,a):
trans=[]
for i in range(c):
tmp=[]
for j in range(r):
tmp.append(0)
trans.append(tmp)
for i in range(c):
for j in range(r):
trans[i][j]=a[j][i]
return trans
PYTHON PROGRAMMING 123

124. MATRIX…
# Main pgm
r=input('Enter no. of rows: ')
c=input('Enter no. of cols: ')
#print 'Enter 1 st matrix n'
a=readmat(r,c)
print 'Enter 2nd matrix '
b=readmat(r,c)
res=matsum(r,c,a,b)
print 'The First Matrix'
printmat(r,c,a)
print 'The Second Matrix'
printmat(r,c,b)
print 'The Sum of Matrix'
printmat(r,c,res)
print 'The trnsponse Matrix'
t=transpose(r,c,res)
printmat(c,r,t)
PYTHON PROGRAMMING 124

125. NAMESPACES
refers to the current snapshot of loaded
names/variables/identifiers/folders
 functions must be loaded into the memory before you
could call them, especially when calling external
functions/libraries
PYTHON PROGRAMMING 125

126. NAMESPACES
import math
print dir()
PYTHON PROGRAMMING 126

127. NAMESPACES
import math, random
print dir()
PYTHON PROGRAMMING 127

128. FROM NAMESPACES
IMPORTING FUNCTIONS
from math import sin, cos, tan
print dir()
PYTHON PROGRAMMING 128

129. NAME BINDING
Import math as m
print m.sqrt()
from math import sqrt as s
print s(2)
PYTHON PROGRAMMING 129

130. Handling Modules
#Create demo.py
import my_module
#Create my_module.py
Print(“Entering My Module”)
Print(“Exiting My Module”)
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131. PYTHON PROGRAMMING 131
* groups related modules
* code calling in several locations
* prevents name collision

132. HANDLING PACKAGES
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133. HANDLING OF PACKAGES
The __init__.py files are required to make Python treat the directories
as containing packages
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134. HANDLING OF PACKAGES:
WILL NOT WORK
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135. HANDLING OF PACKAGES:
WILL WORK
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136. HANDLING OF PACKAGES:
WILL WORK
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137. HANDLING OF PACKAGES:
WILL WORK
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138. SUMMARY
IMPORTATION INVOCATION
importp1.p2.m p1.p2.m.f1()
from p1.p2 importm m.f1()
fromp1.p2.m import f1 f1()
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139. PYTHON PROGRAMMING 139
Divide-and-Conquer is Powerful!

140. SYNTAX ERRORS
 Syntax errors, also known as parsing errors
perhaps the most common kind of complaint you get while you are still
learning Python:
>>> while True print 'Hello world'
File "<stdin>", line 1, in ?
while True print 'Hello world'
^
SyntaxError: invalid syntax
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141. EXCEPTIONS
Even if a statementor expression is syntactically correct, it may cause
an error when an attemptis made to execute it.
Errors detected during execution are called exceptions and are not
unconditionally fatal: you will soon learn how to handle them in Python
programs.
>>> 10 * (1/0)
Traceback (most recent call last):
File "<stdin>", line 1, in ?
ZeroDivisionError: integer division or modulo by zero
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142. EXCEPTIONS
try:
◦ (statements)
except(ValueError)
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143. EXCEPTIONS
import sys
try:
f = open('myfile.txt')
s = f.readline()
i = int(s.strip())
except IOError as e:
print "I/O error({0}): {1}".format(e.errno,e.strerror)
except ValueError:
print "Could not convert data to an integer."
except:
print "Unexpected error:", sys.exc_info()[0]
raise
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144. OOP
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145. OOP
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146. CLASSES
A class is just like a blueprint of a house.
An object is the actual house built from that blueprint.
You could then create numerous houses/objects from a single blueprint.
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147. CLASS
class ClassName:
<statement-1>
.
.
.
<statement-N>
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148. CLASS Example
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class A:
def __init__(self):
pass
def somefunc(self, y):
x=4
c=x+y
print c
b= A()
A.somefunc(b,4) #Classname.method(object, variables)

149. riyazaahil@gmail.com
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150. THANK YOU
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