Class 41 — December 6

I know that you know that

Programming basics — You achieved this semester — Bask in the success

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Look both ways

• Back and ahead

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Agenda

• Be chrestohistorical

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Thanks to the undergraduate TAs for making the course successful

Vienna Donnelly	Hallie Khoung	Brandon Nielsen
Ryan Green	Hao Liu	Jeanine Seaman
Nadia Hassan	Rachel McNamara	Jacob St. Martin
Ann Hoang	Monica Nguyen	Sophia Rogers

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Want to be a TA for CS 1112

• Departmental application

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Test problem solving process

• Read entire problem before coding

• Think about solution stratgey before coding

• Is a choice being made?

• Likely need an if-elif-else statement

• Is something be built? If so,

• Likely need an accumulator and a loop structure

• Initialize accumulator

• total = 0 for summation

• product = 1 for product

• values = [] for list

• Loop to update accumulator

• Is a simple sequence just being examined? A loop is probably necessary unless there are built-in functions to assist (e.g., max(), min(), and len())

for value in sequence :

  ...

• Are the elements of a simple sequence being modified? A for i in range loop is probably necessary

n = len( sequence )

for i in range( 0, n ( :

  value = sequence[ i ]

  ...

  sequence[ i ] = ...

• When is a nested loop necessary?

• Examining an image

for x in range( 0, width ) :

  for y in range( 0, height ) :

  spot = (x, y )

  ...

• Examining a dataset / table

for row in dataset :

  for value in row :

  ...

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Other patterns

• Examine and create dictionaries

• Convert a list of tuples into a dictionary

• Convert a list of two-element lists into a dictionary

• Examine a list with respect to a dictionary

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• Examine a table

• Perform an accumulation

• Process a table on a row by row basis

• Convert cells from strings to numerics

• Check to see if all data cells in the table are of the same form

• Check to see if any data cells in the table are of the desired form

• Check to see if all rows in the table are of the same form

• Check to see if any rows in the table are of the desired form

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• Photo manipulation

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Realizations

• A variable has an identity and a type

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• The value of a variable indicates where the object which it represents can be found

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• Strings are immutable

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• Converting string data to numeric data.

• To get a single integer value nbr from a single numeric representation v

nbr = int( v )

• To get a list of integer values nbrs from a list of numeric representations

nbrs = []

for v in s :

  nbr = int( v )

  nbrs.append( nbr )

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• Python function usage

• A function invocation cannot change the identity of an argument

• All functions return a value either explicitly or implicitly. If there is no explicit return, None is returned.

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Truisms

• The test will cummulative.

• Questions can require in part familiarity with

• Fundamental types; e.g., int, float, and str

• Arithmetic operators; e.g., +, -, *, **, /, //, and %

• Identifiers, keywords, variables, objects, values, and references

• Logical and relational operators; and, or, not, ==, !=, <, >, <=, and >=

• Control constructs; e.g., if, for, and while

• Nested for constructs

• Random value manipulation

• random.seed()

• random.randrange()

• random.choice()

• Builtin-in functions; e.g., print(), input(), int(), float(), str(), max(), min(), len(), type(), and id()

• URLs and web files; e.g., numeric, text and CSV contents

• Ranges

• Data structures and their use: list, dict, tuples, methods and slicing

• Functions, parameters, definitions, and invocations

• Colors and PIL Image

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Final thought

• I say thanks to you — Your presence is a great gift — Brings me happiness

 

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© 2019 Jim Cohoon

Resources from previous semesters are available.