Q&A

MEETUPS - Do you have one?

Some App stuff:

Attributes for specific turtles to make buttons

Python 3

We’ll be using Python 3 in Trinket for all text-based work. Remember your print() functions.

sep=" " lets you specify what the seperator between arguments is. It defaults to a space.

end='\n' lets you specify what to do at the end of the print functin. It defaults to a newline.

You can make anonymous Python 3 trinkets on Trinket for free. If you want the convenience of saving your Python 3 trinkets to your account, you should use code inls560 to get our premium plan at a huge discount of $4.50 a month.

Files

There are a few core actions you should be able to perform on files:

Open them (Dr. Chuck)
Search/extract information from them (Dr. Chuck)
Build a data structure from them (not really Dr. Chuck)
Explore your data (not really Dr. Chuck)
Print a table from your data (not Dr. Chuck)

We’ll do all of these today.

Something Dr. Chuck didn’t cover: the with statement. This is the Pythonic way to open a file:

with open("sales.csv") as file:
  sales_raw = file.read()
  # Or, if you need lines:
  sales_lines = file.readlines()

Otherwise you’ll have to open and close the file handler and it’s a pain.

Lists of Lists

Making a list full of lists gives you some interesting powers. First, you can think of each item in the main list as a row and each item in the interior lists as a cell/column. As long as you keep the lengths constant you’ve got what amounts to a spreadsheet, but in Python!

Here’s how you can visualize a list of lists:

[ [... , ... , ...]
  [... , ... , ...]
  [... , ... , ...]
  [... , ... , ...]
  [... , ... , ...] ]

This one has five rows and three columns.

To work with lists of lists you’ll nee lots of slicing and indexing. Remember the list[x:y:z] syntax.

Let’s get to work! I recommend you read over questions 1-3 briefly and then go straight to exercise 4. Let me orient you briefly.

Dictionaries

Dictionaries are like simple mini databases. They’re great at keeping track of statistics.

Today we’ll use dictionaries of dictionaries that will let you store and retrieve multiple stats about a state. This is a core data analysis skill.

Dictionary exercises today

We’ll spend the whole class working together on your homework. I’m here. Use me. It’s due 11:59pm tonight. Finish in class or make plans to coordinate.

Next time

Dictionary Exercises

More of the same! Except now you’re more skilled.

Take home, ungraded Mid-term

This is exactly the same as the other section of INLS 560. Completing it will get you full credit, and knowing your numerical grade should give you a sense of whether you’ve gotten some of the basics.

This is something that you should treat like a real test. Review Syntax, flow of control, and loops in particular. Trinket does a lot for you in terms of autocomplete and error detection but this will be a paper test with no feedback so make sure you’re not too reliant on those crutches. Try it closed notes and closed book first, then if you need to, look at some class resources and go back with a different color pen to correct your work.