1. Programming
Dr. Jalal Kawash

2. Programming in Jython

3. Variables Assignments
Named memory locations
Hold values
= is the assignment statement
Assigns a value to a variable
x = 10
y = 14
y += 1
z = x+y
x +=5
y = z 10 15 x 15 25 14 y 25 z
Variables Assignments

4. Printing Print messages to the user (screen) print “Hello”
print “Hello World!”
print 5*4
num = 16 – 4
print num
Printing

5. Arithmetic operators Addition: + Subtraction: - Multiplication: *
print 1+2
Subtraction: -
x = y - z
Multiplication: *
print y*x
Division: /
y = x/z
Modulo
print 23%2
Arithmetic operators

6. Basic Data Types Integer Float String Boolean -1, 8, 1119, -17171717
1.6672, ,
String
“Hi”, “Hello”, “Welcome to Jython and Python”
‘Hi’, ‘Hello’, ‘Welcome to Jython and Python’
Boolean
true or false
1 or 0
A = 1 < 3
Basic Data Types

7. def simpleExample(): x = 12 print x y = 2
def simpleExample(): x = 12 print x y = 2*x print y y += x z = y%x print z
Example Program

8. def simpleExample(): x = 12 print x y = 2
def simpleExample(): x = 12 print x y = 2*x print y y += x z = y%x print z
Define a function/program
Called simpleExample()
Executing the function
Example Program

9. def simpleExample(): x = 12 print x y = 2
def simpleExample(): x = 12 print x y = 2*x print y y += x z = y%x print z
Body of the function
indentation defines inclusion
Example Program

10. def simpleExample(): x = 12 print x y = 2
def simpleExample(): x = 12 print x y = 2*x print y y += x z = y%x print z 12 x
Example Program

11. 12 12 output x Example Program
def simpleExample(): x = 12 print x y = 2*x print y y += x z = y%x print z
output 12 12 x
Example Program

12. 12 12 24 output x y Example Program
def simpleExample(): x = 12 print x y = 2*x print y y += x z = y%x print z
output 12 12 x 24 y
Example Program

13. 12 12 24 24 output x y Example Program
def simpleExample(): x = 12 print x y = 2*x print y y += x z = y%x print z
output 12 12 x 24 24 y
Example Program

14. 12 12 24 24 36 output x y Example Program
def simpleExample(): x = 12 print x y = 2*x print y y += x z = y%x print z
output 12 12 x 24 24 36 y
Example Program

15. 12 12 24 36 24 36 output x y Example Program
def simpleExample(): x = 12 print x y = 2*x print y y += x z = y%x print z
output 12 12 x 24 36 24 y 36
Example Program

16. 12 12 24 24 36 36 output x y z Example Program
def simpleExample(): x = 12 print x y = 2*x print y y += x z = y%x print z
output 12 12 x 24 24 36 y 36 z
Example Program

17. 12 12 24 24 36 36 output x y z Example Program
def simpleExample(): x = 12 print x y = 2*x print y y += x z = y%x print z
output 12 12 x 24 24 36 y 36 z
Example Program

18. Reading Input (Keyboard)

19. Reading Input (Keyboard)
Convert string input to
integer
Reading Input (Keyboard)

20. Conditionals

21. A program is a collection of functions
Conditionals
A program is a collection of functions

22. A function can return a value
Conditionals
A function can return a value

23. Conditionals

24. Value returned by int_input()
Conditionals

25. If statement
Conditionals

26. Output Scenarios

27. SKIP
Output Scenarios

28. Flow-Chart (If) Statement before if Test If true false condition
If body
Statement
after if
Flow-Chart (If)

29. def condEx(): a = int_input() if a == 5: print ‘a was 5
def condEx(): a = int_input() if a == 5: print ‘a was 5!’ else: print ‘a was not 5!’
Conditionals

30. If-Then-Else Statements
If logical_condition then do_something
Else do_something_else
Check logical_condition
If true then do_something, skip else part
If false, then skip if and do else part (do_something_else)
If-Then-Else Statements

31. Flow-Chart (If-Else) Statement before if Test If condition true false
If body
Else body
Statement
after if
Flow-Chart (If-Else)

32. If this condition is true
def condEx(): a = int_input() if a == 5: print ‘a was 5!’ else: print ‘a was not 5!’
If this condition is true
Perform if body
Skip Else
Conditionals

33. def condEx(): a = int_input() print ‘Hi’ if a <= 5: print ‘My’ print ‘Dear’ else: print ‘Fi’ print ‘Deer’ print ‘Got it?’
If body
Else body
Conditionals

34. What is the output if user enters 10?
def condEx(): a = int_input() print ‘Hi’ if a <= 5: print ‘My’ print ‘Dear’ else: print ‘Fi’ print ‘Deer’ print ‘Got it?’
What is the output if user enters 10?

35. def condEx(): a = 10 print ‘Hi’ if a <= 5: print ‘My’ print ‘Dear’ else: print ‘Fi’ print ‘Deer’ print ‘Got it?’
False: 10 is not <= 5
Skip If
Perform Else
What is the output?

36. Hi Fi DEER output What is the output? Got it?
def condEx(): a = 10 print ‘Hi’ if a <= 5: print ‘My’ print ‘Dear’ else: print ‘Fi’ print ‘Deer’ print ‘Got it?’
output Hi Fi
DEER
Got it?
What is the output?

37. What is the output if User Enters 3?
def condEx(): a = int_input() print ‘Hi’ if a <= 5: print ‘My’ print ‘Dear’ else: print ‘Fi’ print ‘Deer’ print ‘Got it?’
What is the output if User Enters 3?

38. Write a Jython routine that prints the letter mark, based on the value stored in a numericMark variable.
A if numericMark >= 90
B if numericMark >= 80, but < 90
C if numericMark >=70, but <80
D if numericMark >=60, but <70
F otherwise (numericMark <60)
Exercise

39. Read user input
Convert it to integer

40. If grade >= 90
Print A

41. Else grade <90
If grade >=80
Print B

42. Else grade <80
If grade >=70
Print C

43. Else grade <70
If grade >=60
Print D

44. Else grade < 60
Print F

47. AND OR
NOT
Logical Operators

48. What is the output?

49. What is the output?

50. What is the output?

51. Exercise How would you write the following condition in Jython?
(x < 12) XOR (y >12.5)
In general, how would you write A XOR B
Exercise

52. Arrays and Lists

53. Arrays and Lists An array is a list of numbered (indexed) elements
Names = [‘John’, ’Frank’, ‘Alicia’, ‘Jenn’, ‘James’]
John
Frank
Alicia
Jenn
James 1 2 3 4
Arrays and Lists

54. Arrays and Lists

55. Loops

56. For Loop for i in [0,1,2,3,4,5,6,7,8,9]: print i print 2*i 1 2 3 4 5 61 2 3 4 5 6 7 8 9 2 4 6 8 10 12 14 16 18
For Loop

57. For Loop for i in [9,2,7]: print i+1 for i in range(0,9): print i 10 38 1 2 3 4 5 6 7 8
For Loop

58. for i in range(0,9,2): print i for i in range(0,9,10): for i in range(5,0,-1): 2 4 6 8 5 4 3 2 1
For Loop

59. for i in range(L,H,Inc) i = L i < H i += Inc Inc is positive true
false
For body
Statement
after for
i += Inc
for i in range(L,H,Inc)
Inc is positive

60. for i in range(0,9,3): print ii 3
i < 9
true
Output
print i
i += 3
for i in range(0,9,3): print i

61. for i in range(0,9,3): print ii 3 6
i < 9
true
Output
print i 3
i += 3
for i in range(0,9,3): print i

62. for i in range(0,9,3): print ii 3 6 9
i < 9
true
false
Output
print i 3
i += 3 6
done
for i in range(0,9,3): print i

63. for i in range(H,L,Dec) i = H i > L i += Dec Dec is Negative true
false
For body
Statement
after for
i += Dec
for i in range(H,L,Dec)
Dec is Negative

64. for i in range(4,1,-1): print i3
i > 1
true
Output 4
print i
i -= 1
for i in range(4,1,-1): print i

65. for i in range(4,1,-1): print i3 2
i > 1
true
Output 4
print i 3
i -= 1
for i in range(4,1,-1): print i

66. for i in range(4,1,-1): print ii 3 2 1
i > 1
true
false
Output 4
print i 3
i -= 1 2
done
for i in range(4,1,-1): print i

67. while tank-is-not-full fill-in-gas while house-temperature < set-temperature blow-heat while hungry east
While loop

68. while boolean-condition: body-of-while body-of-while is repeated as long as boolean condition is true
While loop

69. Statement before while
Test
While
condition
true
false
While body
Statement
after while
While Flow-Chart

70. i = 0 while i < 10: print i i += 2 i = 5 while i > 0: i -= 1 2 4 6 8 5 4 3 2 1
While Loop Examples

71. Input: a list of n elements [a0, a1, a2, … , an-1] and one additional element x
Output:
YES, if x is in the list [a0, a1, a2, … , an-1]
NO, otherwise
Example
Input: [12, 5, 6, 100, 3, 1], 12
Output: YES
Input: [12, 5, 6, 100, 3, 1], 2
Output: No
The Search Problem

72. Sequential Search Algorithm (version 1)
Found = NO
i = 0
Compare x with ai
If x == ai Found = YES
i += 1
Repeat until all elements are examined
Print Found
Input: [a0, a1, a2, … , an-1] , x
Sequential Search Algorithm (version 1)

73. Sequential Search Algorithm
Input: Names = [‘John’, ’Frank’, ‘Alicia’, ‘Jenn’, ‘James’], Alicia
Alicia?
Alicia?
Alicia?
John
Frank
Alicia
Jenn
James 1 2 3 4 NO
Found
Sequential Search Algorithm

74. Sequential Search Algorithm
Input: Names = [‘John’, ’Frank’, ‘Alicia’, ‘Jenn’, ‘James’], Alicia
Alicia?
Alicia?
Alicia?
Alicia?
Alicia?
John
Frank
Alicia
Jenn
James 1 2 3 4
YES
Found
Sequential Search Algorithm

75. Sequential Search Algorithm
Input: Names = [‘John’, ’Frank’, ‘Alicia’, ‘Jenn’, ‘James’], Wong
Wong?
Wong?
Wong?
Wong?
Wong?
John
Frank
Alicia
Jenn
James 1 2 3 4 NO
Found
Sequential Search Algorithm

76. Sequential Search Algorithm

77. Sequential Search Algorithm
Once found stop the loop
Sequential Search Algorithm

78. A generic cleaner version

79. Sequential Search Algorithm
Input: Names = [‘John’, ’Frank’, ‘Alicia’, ‘Jenn’, ‘James’], Alicia
Alicia?
Alicia?
Alicia?
John
Frank
Alicia
Jenn
James 1 2 3 4 NO
Found
Sequential Search Algorithm

80. Sequential Search Algorithm
Input: Names = [‘John’, ’Frank’, ‘Alicia’, ‘Jenn’, ‘James’], Alicia
Alicia?
Alicia?
Alicia?
John
Frank
Alicia
Jenn
James 1 2 3 4
No need to examine
YES
Found
Sequential Search Algorithm

81. Magic of Python

82. Algorithm for finding minimum of a list
Given a list L
If L is empty return Undefined
Min-so-far = L[0]
For i in range(1, len(L)):
If L[i] < Min-so-far:
Min-so-far = L[i]
Return Min-so-far
Algorithm for finding minimum of a list

83. Min of a list John James James < John 1 Min-so-far Marie 2 John
James
James < John 1
Min-so-far
Marie
John 2
Frank 3
Alicia 4
Min of a list

84. Min of a list John James 1 Min-so-far Marie James 2 Marie > James
James 1
Min-so-far
Marie
James 2
Marie > James
Frank 3
Alicia 4
Min of a list

85. Min of a list John James 1 Min-so-far Marie James 2 Frank 3
James 1
Min-so-far
Marie
James 2
Frank 3
Frank < James
Alicia 4
Min of a list

86. Min of a list John James 1 Min-so-far Marie Frank Alicia 2 Frank 3
James 1
Min-so-far
Marie
Frank
Alicia 2
Frank 3
Alicia 4
Alicia < Frank
Min of a list

87. Code for Algorithm Min

88. The Sorting Problem Input: a list of n elements [a0, a1, a2, … , an-1]
Output:
The same list sorted in ascending order
Example
Input: [12, 5, 6, 100, 3, 1]
Output: [1, 3, 5, 6, 12, 100]
The Sorting Problem

89. Selection Sort Algorithm
Given a list L
SortedL = []
For i in range(0,len(L)):
minElement = Min(L)
SortedL.append(minElement)
L.remove(minElement)
Return SortedL
Selection Sort Algorithm

90. Selection Sort List L List SortedL John Alicia James 1 Marie 2 Frank 3
James 1
Marie 2
Frank 3
Alicia 4
Selection Sort

91. Selection Sort List L List SortedL John Alicia James Frank 1 1 Marie 2
James
Frank 1 1
Marie 2
Frank 3
Selection Sort

92. Selection Sort List L List SortedL John Alicia James Frank 1 1 Marie
James
Frank 1 1
Marie
James 2 2
Selection Sort

93. List L
List SortedL
John
Alicia
Frank 1
Marie
James 1 2
Selection Sort

94. List L
List SortedL
John
Alicia
Marie
Frank 1 1
James 2
Selection Sort

95. Selection Sort List L List SortedL John Alicia Marie Frank 1 1 James 2
Marie
Frank 1 1
James 2
John 3
Selection Sort

96. Selection Sort List L List SortedL Alicia Marie Frank 1 James 2 John 3
Marie
Frank 1
James 2
John 3
Marie 4
Selection Sort

97. Selection Sort List L List SortedL Alicia Frank 1 James 2 John 3 Marie
Frank 1
James 2
John 3
Marie 4
Selection Sort

98. Selection Sort Program

99. There is a ready min(L) function in Jython
There is a ready sort, L.sort() as well
Does not use selection sort, though

100. Nested For Loops