Another Approach to Building Exercise Problems

Here recently I've been working with those in my developer book club group to get some of the others to be presenters, and with that we've gone through and covered chapters 2 and 3 of Effective Python with others from the group acting as presenters, and the two presenters took a different approach to coming up with the exercise problems than I did, and it worked pretty well, so I figured that I'd go over their approach a little bit here.

To start off, here's a small sampling of some of the exercise problems and their answers for the Effective Python chapter 2 presentation, as presented by Nathan Malloch:

from typing import List
from collections import defaultdict

print('create a list with 10 elements')
l = [4, 65, 34, 56, 78, 23, 54, 76, 653, 66]
print(l)

print('print the last 3')
print(l[-3:])

print('print all but the last 5')
print(l[:-5])

print('print the first 4')
print(l[:4])

print('make a referenced copy of the list and print them')
g = l
print(g)
print(l)

print('remove the last two indexes from the first list while also updating the second')
l[:] = l[:-2]
print(g)
print(l)

print('make a deep copy of the list, print both')
b = l[:]
print(b)
print(l)

print('remove 2 through 4 index of first list, but don\'t effect the second list')
l[2:5] = []
print(l)
print(b)

So here we see an approach where instead of giving a single, high level problem to solve, we are given problems that are much closer to the code and are very clearly tied to the principles taught in chapter 2.

I find that this approach and the high level approach can both work well in helping to emphasize and teach different things. This low level approach allows you to focus in on a specific language feature and test it in many different ways so as to get an in depth understanding of how that specific feature works, whereas in the high level approach, you aren't told specifically what tools or features to use, and choosing which features to use is part of the problem solving process.

This makes me think of an analogy in math. In your typical math textbook you will run into two types of problems. The first type are your standard problems, which will typically look something like this:

    6
   x3 
    

And then there's the story problem, which looks a bit more like this:

• A box of donuts has 6 donuts, and you have 3 boxes. How many donuts do you have?

Now with the first type of problem, solving is pretty straightforward. You're expected to practice your multiplication, like so:

    6
   x3 
   18

The second type of problem also involves setting up the problem, and the best setup would turn out the same:

    6
   x3 
   18

But that being said, it's quite valid for someone to choose to solve the problem in this way, even if it isn't quite ideal:

    6
    6
   +6 
   18

So with that, a story problem gives the opportunity to exercise your ability to choose the right tool for the job. On the flip side of the coin, though, standard practice problems give the ability to explore important concepts that don't easily fit into an nice little story, such as:

(2+i)(3-4i)=

These same concepts apply to high level and low level exercise problems for programming, where high level also exercises tool selection, and low level allows experimentation with principles that would be hard to fit into a concise story problem.

There is also another benefit to low level exercise problems for the presenter, which is that they are easier to come up with. There's no need to come up with a story, and no need to try and fit unrelated features into the same problem.

One word of caution when using this style, though. Because of how small and simple the problems are, it can be tempting to prepare more material than can be covered in a single meetup. Just as with the story problems, it's important that you don't try to teach everything from the chapter, but instead pick out a few of the more important principles to practice.

And it's important to expect that as you're presenting the problem, that people in the group will want to test and experiment with each of the problems along the way, seeing what happens with one tweak or another. It is important that there is time enough for this experimentation, because that's what's going to help it to stick in people's minds.

So with that, feel free to mix it up between high level and low level exercise problems. They both make for great ways to help solidify the ideas being taught.