Class 5 – Friday, September 4

It's all about you

Show understanding — Put it altogether now — Yes you all can do

Help crush breast cancer — For your friends and families— Not be asunder

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Talk before knowing — Something very tough for me — I wonder why that is

CS is alright — Paying attention is key — It can be fun too

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Look both ways

• Back or ahead

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Downloads

• Program casting.py

• Program being_powerful.py

• Program trio.py

• Program complimenter.py

• Program tao.py

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Agenda

• Further expand our communication skills

• Enlightenment

• Introduce objects

• Introduce Python string manipulation capabilities

• Get adept at casting

• Demonstrate your own chresthomatics abilities by solving and submitting problem solutions before the end of class.

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All future homework requirements

• A numeric value display must be from the value of a variable; i.e., there will never be arithmetic calculations within a print() statement.

• All variables should be named indicating their purpose/usage.

• Always end each prompt with a space; e.g., input( 'What is something you consume daily?: ' )

• The testing of your programs will use inputs different from those shown in problem discussion.

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To do list

• Check out the the activities for next class

• Ensure familiarity of the past by carefully examining artifacts, epistles, and videos.

• Complete homework 06 as soon as possible for your sake.

• Definitely check out the string module. It will be a major topic next week

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Program casting.py

• Introduce type conversion — constructing a value of one type from a value of another type

• Major conversions

• int( s ): returns the integer constructed from integer numeric string s

• int( d ): returns the integer part of decimal d

• float( s ): returns the decimal constructed from numeric string s. There maybe loss of precision

• float( i ): returns the decimal constructed using integer i. There maybe loss of precision

• str( x ): returns a string version of x

• A possible program run

integer_string = '112358'

decimal_string = '93.86'

decimal_number = 9.04

integer_number = 1112

i1 = int( integer_string )

i2 = int( decimal_number )

f1 = float( integer_number )

f2 = float( decimal_string )

112358 + 9 = 112367

1112.0 + 93.86 = 1205.86

nbr1 = 14

nbr2 = 1.5

s1 = str( nbr1 )

s2 = str( nbr2 )

'14' + '1.5' = '141.5'

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Program being_powerful.py

• Problem

• Prompt and get an integer number (the base for the computation)

• Prompt and get a decimal number (the exponent for the computation)

• Compute the value of the integer to power of the decimal number

• Print the result of the computation

• What the solution offers

• Uses the built-in cast functions int() and float() to convert numeric strings into the numbers they represent.

• Three possible program runs

Enter base (integer): 2

Enter exponent (decimal): 0.5

 

1.4142135623730951

Enter base (integer): 11

Enter exponent (decimal): 3.14

 

1861.971509290233

Enter base (integer): 9

Enter exponent (decimal): 99.9

 

2.132201+95

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Program trio.py

• Problem

• Prompt user for three words

• Split the input into separate words

• Print the words on separate lines

• What the solution offers

• Introduces the string member function split(). Its called a member because every string can be called upon to produce a split up version of itself. The value of a split() invocation is the list of substrings (words) that make up the string being told to split(). The function is handy for breaking up user input into its individual parts.

• The final version of the program shows that every string has a member function for inspecting itself. The split() function hands back the list of words that make up the string.

• Three possible program runs

What are your three favorite words: peace joy friends

 

peace

joy

friends

What are your three favorite words: you me us

 

you

me

us

What are your three favorite words: subcontinental nudiustertian uncopyrightable

 

subcontinental

nudiustertian

uncopyrightable

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Program complimenter.py

• Problem

• For a single user-supplied integer age, print out a tasteful compliment based on the supplied age.

• Requirements

• The faux (complimentary) age is the user-supplied age minus five years.

• The faux age is to be integer.

• The program does not attempt to get more than one input from the user.

• Three different program runs

• The above section header means what it literally says. The below boxes each show a different program run; i.e., your program is to perform a single age calculation each time it is run.

  Enter your age: 19

  You don’t even look 14

  Enter your age: 111

  You don’t even look 106

  Enter your age: 20

  You don’t even look 15

• Suggested code outline

• Prompt user to supply an age

• Convert user reply to integer

• Compute supposed age

• Print the result of the computation

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Program tao.py

• Problem

• Prompt and input from user both an integer width and height of a rectangle

• Split the input into two strings

• Convert strings into integers

• Compute the product

• Produce the result

• What the solution offers

• Shows the proper way of converting the splitting of a string made up of numberic characters into individual numbers.

• Three possible program runs

Enter rectangle width and height (integers): 5 6

 

30

Enter rectangle width and height (integers): 2 71

 

142

Enter rectangle width and height (integers): 3 14

 

42

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© 2020 Jim Cohoon

Resources from previous semesters are available.