Class 12 – Monday, September 23

In a loop, a loop — Nesting, but not like a bird — Repeating again

Look out my window — And see random acts of grace — By everyone

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Look both ways

• Back or ahead

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Agenda

• Extend print() function functionality

• Introduce randomness

• Doing loop the loops

• Introduce pillow.

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For the fun of it

• Reveal one of your super power(s).

• Share a selfie.

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To do list

• Review class artifacts.

• Complete homework.

• Install pillow.

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Downloads

• Program thats_printastic.py

• Program so_random.py

• Program and_the_winner_is.py

• Program nested_looper.py

• Program dataset.py

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Optional printing

• Program thats_printastic.py

• Introduces the optional closing parameter end="..."

Program run

Wa-Hoo-Wa

Rah-Rah-Rah

Wa-Hoo-Wa!!!Rah-Rah-Rah

Wa-Hoo-Wa !!! Rah-Rah-Rah

t-a-t-t-a-r-r-a-t-t-a-t-

saippuakivikauppias

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Introducing module random

• Program so_random.py

• Demonstrates some simple usage of random module function randrange()

• Some program runs

Enter two integers: 10 100

Four random values from interval [ 0, 10 ): 7 4 3 5

Four random values from interval [ 0, 100 ): 15 28 64 87

Enter four integers: 10 20 75 100

Four random values from interval [ 0, 10 ): 4 4 8 8

Four random values from interval [ 0, 100 ): 22 64 2 80

Enter two integers: 10 100

Four random values from interval [ 0, 10 ): 1 2 8 6

Four random values from interval [ 0, 100 ): 57 63 81 18

Enter four integers: 10 20 75 100

Four random values from interval [ 10 , 20 ): 11 11 19 15

Four random values from interval [ 75 , 100 ): 89 85 76 99

Enter two integers: 10 100

Four random values from interval [ 0, 10 ): 3 5 3 6

Four random values from interval [ 0, 100 ): 29 12 32 5

Enter four integers: 10 20 75 100

Four random values from interval [ 10 , 20 ): 13 14 16 19

Four random values from interval [ 75 , 100 ): 92 98 75 75

Enter two integers: 2 10

Four random values from interval [ 0, 2 ): 1 0 0 1

Four random values from interval [ 0, 10 ): 6 6 2 8

Enter four integers: 0 8 31 39

Four random values from interval [ 0 , 8 ): 7 2 1 3

Four random values from interval [ 31 , 39 ): 37 36 32 37

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• Program and_the_winner_is.py

• Demonstrates some simple usage of random module function randrange()

• Some program runs

Enter a string: abcdefghij

Four random characters from string abcdefghij : e a j d

Enter some words: th fo ju ov th la lo

Four random words from list ['th', 'fo', 'ju', 'ov', 'th', 'la', 'ol'] : ov lo la ov

Enter a string: abcdefghij

Four random characters from string abcdefghij : a i b h

Enter some words: th fo ju ov th la lo

Four random words from list ['th', 'fo', 'ju', 'ov', 'th', 'la', 'ol'] : th fo th ju

Enter a string: simultaneously

Four random characters from string simultaneously : i y m t

Enter some words: 31 41 597 2 71

Four random words from list ['31', '41', '597', '2', '71'] : 71 597 31 71

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Nested looping

• Program nested_looper.py

• Introduces nested looping. Where for a user-supplied n, the program loops n times and on the i^th iteration prints a line of the form

i: 0 1 2 ... i

• Two sample program runs

Enter number: 5

row 0: 0

row 1: 0 1

row 2: 0 1 2

row 3: 0 1 2 3

row 4: 0 1 2 3 4

Enter number: 10

row 0: 0

row 1: 0 1

row 2: 0 1 2

row 3: 0 1 2 3

row 4: 0 1 2 3 4

row 5: 0 1 2 3 4 5

row 6: 0 1 2 3 4 5 6

row 7: 0 1 2 3 4 5 6 7

row 8: 0 1 2 3 4 5 6 7 8

row 9: 0 1 2 3 4 5 6 7 8 9

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Examining a list whose elements are lists

• Such lists are often called tables or datasets

• Program dataset.py

• Demonstrates looping through a two-dimensional in different ways

Program run

[['A', 'B', 'C'], ['D', 'E', 'F'], ['G', 'H', 'I'], ['J', 'K', 'L']]

['A', 'B', 'C']

['D', 'E', 'F']

['G', 'H', 'I']

['J', 'K', 'L']

row 0: ['A', 'B', 'C']

row 1: ['D', 'E', 'F']

row 2: ['G', 'H', 'I']

row 3: ['J', 'K', 'L']

row 0 : ['A', 'B', 'C']

column 0 of row 0 : A

column 1 of row 0 : B

column 2 of row 0 : C

row 1 : ['D', 'E', 'F']

column 0 of row 1 : D

column 1 of row 1 : E

column 2 of row 1 : F

row 2 : ['G', 'H', 'I']

column 0 of row 2 : G

column 1 of row 2 : H

column 2 of row 2 : I

row 3 : ['J', 'K', 'L']

column 0 of row 3 : J

column 1 of row 3 : K

column 2 of row 3 : L

A B C

D E F

G H I

J K L

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© 2019 Jim Cohoon

Resources from previous semesters are available.