EGR 103/Concept List Fall 2019

This page will be used to keep track of the commands and major concepts for each lab in EGR 103.

Lectures

Lecture 1 - Introduction

• Class web page: EGR 103L; assignments, contact info, readings, etc - see slides on Errata/Notes page
• Sakai page: Sakai 103L page; grades, surveys and tests, some assignment submissions
• Piazza page: Piazza 103L page; message board for questions

Lecture 2 - Programs and Programming

• To play with Python:
  • Install it on your machine or a public machine: Download
  • Use a Duke container with Spyder: Containers - note - these do not have access to your Duke files. More on how to connect that later.
• Quick tour of Python
  • Editing window, variable explorer, and console
  • Variable explorer is your friend
• From Dewey - programming language typically have ability to work with input, output, math, conditional execution, and repetition
• Hilton and Bracy Seven Steps
• Class work developing algorithm for program to determine if a number is prime

Lecture 3

• 7 Steps for finding prime numbers
• prime program -- includes intro to input(), if tree, for loop, print(), remainder %

Lecture 4

• Function definitions
  • Positional and key word arguments (kwargs)
  • Default values
  • Returns tuples -- can be received by a single item or a tuple of the right size
• Aquarium

Lecture 5

• print() and format specifications: link
  • Main components are width, precision, and type; sometimes initial +
  • e and f can print integers as floats; d cannot print floats
• relational and logical operators - how they work on item, string, list, tuple
• if trees
• while loops
• for loops
  • NOTE: in the case of

for y in x

If the entries of x are changed, or really if x is changed in a way that its location in memory remained unchanged, y will iterate over the changed entries. If x is changed so that a copy first has to be made (for example, it is set equal to a slice of itself), then y will iterate over the original entries. Note the differences between:

x = [1, 2, 3, 4, 5]
for y in x:
    print(x, y)
    x[4] = [0]
    print(x, y)

and:

x = [1, 2, 3, 4, 5]
for y in x:
    print(x, y)
    x = x[:-1]
    print(x, y)

• counting characters program

# letter_typing.py from class:

def check_letters(phrase):
    vowels = "aeiou"
    numbers = "0123456789"
    consonants = "bcdfghjklmnpqrstvwxyz"
    # vowels, numbers, consonants, and other in that order
    count = [0, 0, 0, 0]
    
    for letter in phrase:
        if letter.lower() in vowels:
            count[0] += 1
        elif letter.lower() in numbers: # .lower not really needed here
            count[1] += 1
        elif letter.lower() in consonants:
            count[2] += 1
        else:
            count[3] += 1
            
    return count

out = check_letters("Let's go Duke University 2018!")
print(out)

• Question in class: does Python have ++ or -- operators; it does not. You need x += 1 or x -= 1

Lecture 7

• Distinction between == and i
• Iterable types and how they work (list, tuple, string
• Things that do not change memory address of a list (and therefore change what a loop iterates over):
  • +, .append(), .extend(), .insert(), .remove(), .pop(), .sort(), .reverse(), .clear()
• Things that do change memory address of a list:
  • Total replacement, replacement by self-slice, making a copy
• Singularity functions
  • Unit step \(u(t)\)
  • See Singularity Functions for way too much information - more in lab!
    • Singularity_Functions#Alternate_Names_for, Singularity_Functions#Building_a_Mystery_Signal, and Singularity_Functions#Accumulated_Differences might be particularly helpful!

Labs

• Lab 1
  • Unix commands: pwd, cd, ls, mkdir, wget, tar, cp, latex, dvipdf, evince, xeyes
  • Other concepts: MobaXterm, XQuartz, ssh
  • Windows permissions were covered, but were only needed during this one lab.
  • Mounting CIFS drives was covered, but will not be needed for lab 1.
  • Three parts of lab:
    • Once only ever: creating EGR 103 folder, setting Windows permissions
    • Once per lab: creating lab1 folder, wget-ting files, tar expansion, duplicate lab skeleton
    • Doing work: changing to lab1 folder; using emacs, latex, dvipsd, and evince correctly
  • Work on lab every day - at least logging in, changing directories, using (emacs, latex, dvipdf, evince)
  • Work a little at a time to help with debugging