Class 12 – Monday, September 21

Building and examining lists

An optimist thinks — Elevator close button — Really does something

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Look both ways

• Back or ahead

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Agenda

• Extend print() function functionality

• Introduce nested loops

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• Program thats_printastic.py

• Program c_looper.py

• Program nested_looper.py

• Program rc_looper.py

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To do list

• Reveal one of your super power(s)

• Share a selfie

• Review class artifacts.

• Complete the homework

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Program thats_printastic.py — introduce print() optional closing parameter end="..."

Task

• The optional end="..." parameter for a print() function allows changing from its default action of starting the next print on a new line.

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-

s a i p p u a k i v i k a u p p i a s

saippuakivikauppias

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Program c_looper.py

Task

• For a user-supplied n, prints a line of the form

row : 0 1 2 ... n-1

Some program runs

Enter number of columns: 5

row : 0 1 2 3 4

Enter number of columns: 12

row : 0 1 2 3 4 5 6 7 8 9 10 11

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Nested looping — program nested_looper.py

Task

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

row r : 0 1 2 ... r

Some program runs

Enter number of rows: 4

row 0 : 0

row 1 : 0 1

row 2 : 0 1 2

row 3 : 0 1 2 3

Enter number of rows: 6

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

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Nested looping — program rc_looper.py

Task

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

r+0 r+1 ... r+n-1

Some program runs

Enter number of rows: 5

0 1 2 3 4

1 2 3 4 5

2 3 4 5 6

3 4 5 6 7

4 5 6 7 8

Enter number of rows: 10

0 1 2 3 4 5 6 7 8 9

1 2 3 4 5 6 7 8 9 10

2 3 4 5 6 7 8 9 10 11

3 4 5 6 7 8 9 10 11 12

4 5 6 7 8 9 10 11 12 13

5 6 7 8 9 10 11 12 13 14

6 7 8 9 10 11 12 13 14 15

7 8 9 10 11 12 13 14 15 16

8 9 10 11 12 13 14 15 16 17

9 10 11 12 13 14 15 16 17 18

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© 2020 Jim Cohoon

Resources from previous semesters are available.