Class 7 – Wednesday, September 9

Make Bill Murray proud

Take another step — Chrestomathics awaits you — Feel the momentum

Camouflage not needed — Do not hide what makes you, you — You are welcomed here

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Look both ways

• Back or ahead

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What I want to accomplish today

• Complete our introduction of the basics of Python programming by examining a program that converts Celsius temperatures to Fahrenheit temperature. The program is important as makes us explicitly aware of operator precedence.

• To solve problems of greater complexity we need to add to our programming toolbox. In particular, we need to be able to decompose complex inputs into manipulable data and then be able to process the data no matter it size.

• Such abilities requires deeper awareness of string manipulation and the ability to iterate; that is, be able to repeat actions so that all the data can be processed. The slang word for iteration is looping.

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I should not show this complimenter.py interaction, but I am going to do it anyway

How old are you? 24

If aliens descended from space, they would classify you as 19

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Agenda

• Continue exploration of the basics of problem solving — getting data, performing computation, and displaying information. Along the way we will develop an appreciation for expression evaluation and formulation

• Continues introduction to the string type str

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Downloads

• Program temperature.py

• Considers operator precedence

• Program break_the_bank.py

• Continues chrestomathics

• Program indexing.py

• Weird world of indexing in Python

• Program lickety_strip_and_split.py

• Explores the string member functions strip() and split().

• Program love_is_all_you_need.py

• Introduces for loops that process a range of values.

• Program thats_amore.py

• Introduces for loops that process a list of data.

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To do list

• Review class artifacts

• Finish homework

• Check out other Python built-in functions

• Reread about Python string capabilities.

• Reread problem-solving epistle

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Program temperature.py

• Prompts user for a integer Celsius temperature and separately computes its integer and decimal Fahrenheit equivalent using the formula

• Two different possible runs

Enter Celsius temperature: 24

24 C = 75.2 F

24 C = 75 F

Enter Celsius temperature: 8

8 C = 46.4 F

8 C = 46 F

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Program break_the_bank.py

• With a single prompt, it gets from the user four values in the following order: number of quarters, dimes, nickels, and pennies. Computes and displays how much the coinage is worth.

• Two different possible runs

Number of quarters, dimes, nickels, and pennies: 27 14 28 18

Coinage

    27 quarters

    14 dimes

    28 nickels

    18 pennies

are worth 9.73 dollars

Number of quarters, dimes, nickels, and pennies: 1 2 3 4

Coinage

    1 quarters

    2 dimes

    3 nickels

    4 pennies

are worth 0.6400000000000001 dollars

• Recommend that you avoid the ugliness of the last run and use the built-in function round().

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Program indexing.py

• Explores selecting an individual character from a string — indexing

• Introduces indexes.

Program output

### [] is the string index operator

s: sequoia

  0123456

n = len( s ): 7

s[ 0 ]: s

s[ 4 ]: o

s[ n-1 ]: a

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Program lickety_strip_and_split.py

• Explores the string member functions strip() and split().

q: ' There is a door open to walk through '

### mis-attempted stripping

q.strip()

q: ' There is a door open to walk through '

### stripping

s = q.strip()

q: ' There is a door open to walk through '

s: 'There is a door open to walk through'

### splitting

f: 'bananas $0.69'

c: 'SEAS CS 1112'

fruit, price = f.split()

bananas costs $0.69 per pound

school, subject, number = c.split()

School: SEAS subject: CS number: 1112

### list making

list1 = f.split()

list2 = c.split()

list1: ['bananas', '$0.69']

list2: ['SEAS', 'CS', '1112']

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Program love_is_all_you_need.py

• Prints the adage Love is all you need the requested number of times

Some program runs

Enter number of lines to be printed: 5

Love is all you need

Love is all you need

Love is all you need

Love is all you need

Love is all you need

Enter number of lines to be printed: 1

Love is all you need

Enter number of lines to be printed: 0

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Program thats_amore.py

• Prompts its user for three words and prints them one per line

• Prompts its user for several words and prints them one per line

• A possible program run

Enter three words: love amore salangha

love

amore

salangha

Enter several words: amar 'ahbak liebe cinta Ài

amar

'ahbak

liebe

cinta

Ài

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© 2020 Jim Cohoon

Resources from previous semesters are available.