Notes for Session 10

5/10/2018

A collection of notes to go over in class, to keep things organized.

Lightning Talks

Anyone missed their chance?

Logistics, announcements (from Hosung)

Office hours

Hosung’s: 3-5pm, Saturday, 5/12/2018 @ Study Room #1 (not the usual #9), Foster Business Library, Paccar Hall

Also available online through Zoom. Email for appointment!

Grades

Canvas gradebook is now fully updated. The last two assignments (OO mailroom, funciontal mailroom) are not yet included in the total percent score. All others are included (submissions still accepted), and no submissions are treated as 0. Do make sure your gradebook entries are accurate and contact us otherwise. Do note that 80% assignment score is a requirement for an SC (Successful Completion) grade.

Merge conflicts

We’ve got a number of merge conflicts in PRs, which keep us from completing/merging those PRs. We need to fix them in person, so I’ll contact each affected individual and try to sort this out. I also should have mentioned in last class that everyone should copy the example code files to their own student directory, not working directly on those files (in the example directory) that are pulled from upstream… My fault if merge conflicts were on that directory. I still saw strange merge conflicts, so we’ll be fixing them in person in this class during the break.

Last 2 assignments

Feel free to combine the last 2 assignments (OO mailroom & functional mailroom) and submit just one PR. If your single submission includes both OO-redesigned mailroom and required functional features, we’ll mark both assignments as complete for such a submission.

Also feel free to build on the solution to the previous mailroom assignment that’s posted at https://github.com/UWPCE-PythonCert-ClassRepos/Sp2018-Accelerated/blob/master/solutions/Lesson06/mailroom2.py .

Issues that came up during the week.

When to make a method or property?

It is a good idea to make a property to access information in your class that requires “inside information”, For example, in a Donor class:

@property
def maxdonation(self):
    return max(self.donations)

This way, client code can get the maximum donation without knowing, or caring, how the donations are stored in the class.

However, there is no need to create a property to “hide” something that is already part of the public API:

@property
def namelength(self):
    return(len(self.name))

There is no point to this – a_donor.name is expected to be a string – so if you want to know how long it is, you can simply do: len(a_donor.name)

You do want to use properties to “hide” implementation details – but the name attribute being a string is part of the API, not an implementation detail.

Anything else from OO mailroom?

Supplements to Functional Programming in Python (from Hosung)

Searched the web for some good references on the topic, and found some (seemingly) good ones that I liked. We’ll go over some examples from them:

https://anandology.com/python-practice-book/functional-programming.html : Really liked the trace and the memoize decorations. See how the original `fib(n)` can be inefficient and also see why using the trace decoration and how it can be improved usng the memoize (not a typo!) decoration. Note that recursion is not much considered as functional, though functional programming relies heavily on recursion. Also note that decorators will be covered in more detail in the second course of the program, and they may not be considered pure functional (closures, mutating environment, …).

https://maryrosecook.com/blog/post/a-practical-introduction-to-functional-programming : A seemingly good read on functional programming principles with examples in Python

http://www.cs.rpi.edu/~sibel/csci1100/fall2017/lecture_notes/lec24_functional.html : Seemingly good examples on lambda. An example problem: Given a list of points in 2D coordinates, return a list of the points in the order of distance from the origin (`(0,0)`). What about in the order of distance from any point `(x,y)`?

The Next Class

Next quarter, you’ll finish up the core of the Python language, then go into depth on some of the more advanced features of the language. Finally, we’ll do a bit with using Python with other tools, such as databases.

Here’s an Outline:

Functional Programming 2

  • Comprehensions
  • Lambda
  • Iterators and Iterables
  • Generators
  • Itertools

Functional Programming 3

  • Closures and Currying
  • Itertools
  • Functools

Advanced Python Language Constructs

  • Decorators
  • Context Managers
  • Recursion

Metaprogramming

  • Namespaces
  • Introspection
  • Metaclasses
  • Class Decorators

Debugging & Logging

  • Logging module
  • Syslog
  • pdb/ipdb

Advanced Testing

  • Linting
  • Coverage
  • The unittest Module
  • Fixtures
  • Mocking

Relational Databases

  • SQL
  • ORMs: PeeWee
  • Sqlite
  • Postgresql

NoSQL Databases

Object/Document, Key/Value and Graph Databases

  • Schema vs “Schemaless”
  • Mongo
  • Redis
  • Neo4j

Profiling & Performance

  • Timing
  • Profiling
  • PyPy
  • Cython

Concurrency & Async Programming

  • Concurrency
  • Threading and Multiprocessing
  • Message Queues
  • Async

End of Quarter:

We will review PRs through Monday.