What’s a lightbulb that has gone on for you?

For some reason, I used to have trouble with functions in Python. No idea why. They’re similar enough to R that it feels like I shouldn’t have had a problem, but I never quite got it. In this class, one of the first things I did was write a function to draw an arbitrarily-many-sided polygon. For some reason, it finally just clicked.

Here’s the polygon function:

def draw_polygon(turtle, color, sides, size, x, y):
  turtle.penup()
  turtle.color("black")
  turtle.shape("turtle")
  turtle.fillcolor(color)
  turtle.goto(x,y)
  turtle.pendown()
  turtle.begin_fill()
  for i in range(sides):
    turtle.forward(size)
    turtle.left(360/sides)
  turtle.end_fill()
  turtle.setheading(0)

Describe some confusion you’ve experienced.

I honestly hate Python documentation. R documentation always lists the args, what they do, examples of acceptable input, and then has code samples below that show how to get certain outputs. I’ve had a lot of trouble adjusting to Python’s documentation because everything is less clear and there’s often no examples. I’m starting to get more used to it, and I believe that will help me learn other languages in the future, but it’s definitely been work.

What’s still fuzzy for you? What will you do to make sure you can resolve your fuzziness?

So far, I think I understand most things pretty well, but I don’t yet understand scope in Python. For some reason, when I try to call a function inside a function def statement, it doesn’t work. I haven’t yet figured out what I’m doing wrong, but I’ll be investigating StackOverflow and the docs to see.

The code I’m still having trouble with is below:

def draw_random(turtle, rand, color = "black", lines = 10, line_length = 10):
  turtle.penup()
  turtle.color(color)
  turtle.shape("turtle")
  turtle.goto(0,0)
  turtle.pendown()
  for i in range(lines):
    turtle.forward(line_length)
    if rand % 2 == 0:
      turtle.right(rand)
    else:
      turtle.left(rand)
  turtle.setheading(0)

I tried to call the randrange() function within this def statement, but I kept getting an error that said the function wasn’t defined. I had already loaded the package earlier in the script. I assume this was a problem of scope and the def statement doesn’t have access to imported functions for some reason. So, I tried defining a variable that calls randrange(), called rand, but I’m having the same problem. I’ll figure it out eventually, but I haven’t sat down and done so yet.

What problem solving strategies have been working for you?

I’ve gotten pretty good at debugging over the last year or so. Any time I run into an error, I always hunt down where the problem is, search online for similar problems, look up the documentation if I’m using a packaged function, etc… Once I’ve done all of that, I start tweaking things that I think might be wrong. If I try several without any progress, sometimes I’ll start from scratch (if the code isn’t too long). If it’s an integral part of a larger script, I’ll delete that block and rewrite it. One thing I do a lot when I have problems with a complicated block is to start from scratch and build several simple iterations leading up to what I want. So I’ll start with simple things like assignment and basic operations, make sure everything is working, then move to conditionals and control structure. I’ll keep adding on to what I know works until something breaks, then I’ll go back to hunting down why whatever it is broke. So far, I haven’t run into a problem that couldn’t be solved this way.

My functional trinket

An iframe of my functional trinket can be found below.