Mailman 3 July 2014 - Edu-sig

a short essay about programming
by kirby urner Dec. 8, 2022

Dec. 8, 2022

A common "error" (not too serious) that I see in beginning Python (and no doubt other languages, but Python is the one I'm teaching), is having a while condition that appears to put a lid on things, but then the flow all leaks away through break statements, such that the "front door" condition is never revisited. while guess != secret: guess = int(input("Guess?: ") if guess == secret: print("You guessed it!") break else: print("Nope, try again...") What's messed up about the above code is you never really go back to the top in the case where you'd get to leave. Rather, you exit by the back door, through break. So in that case, wouldn't have been simpler and more elegant, even more "correct" (dare I say it) to have gone: while True: # no ifs ands or buts guess = int(input("Guess?: ") if guess == secret: print("You guessed it!") break else: print("Nope, try again...") I see lots of heads nodding, and that could be the end of the matter, but then a next question arises: wouldn't this also be a more correct solution?: while guess != secret: guess = int(input("Guess?: ") if guess == secret: print("You guessed it!") continue # instead of break else: print("Nope, try again...") We're back to having a variable while condition, not a boolean constant, but this time we actually exit by means of it, thanks to continue or... while guess != secret: guess = int(input("Guess?: ") if guess == secret: print("You guessed it!") else: print("Nope, try again...") ... thanks to no continue. This last one is getting a thumbs up, but then I'd pause here and say "continue" can be easier on the eyes. It's unambiguous where it takes you, in contrast to having to scan on down the gauntlet, looking for possibly other open doors. "What happens next" should not require scanning ahead too far. Help us not to get lost. Be a civic-minded coder. I'm thinking of a programming style that advises two things: (a) if you use a while condition that's variable, that's expected to change, then your goal should be to always exit because of that, i.e. that should be your only exit point. Even if some other criterion suggests exiting, you have the option to flip that "lid" at the top, to crack that front door, and bounce the ball out. (b) which is why 'continue' is your friend. You are showing the user where your 'break' statements are, except you don't use "break" statements, as you've given a non-constant condition, and your aim is to make that your ONLY exit point. In short: never use break to exit a while loop unless your condition is while True. Instead, always flip the condition and exit through the font door. However, as soon as I make that rule I can think of good reasons to break it. The other programmers in the room are shaking their heads. Won't we lose information, needed elsewhere in the program, if we "artificially" force a True condition to False. Aren't we, in effect, lying? That concern could be addressed. Keep all the info true, just treat the "lid condition" (it "keeps a lid on it") as a flag. Go ahead and remember the user's guess. allowed = 5 tries = 1 exit = False while not exit: # no other way out guess = int(input("Guess?: ") if guess == secret: print("You guessed it!") exit = True # instead of break continue print("Nope, try again...") tries += 1 if tries == allowed: print("You've maxed out") exit = True continue I think we all understand the main issue: writing reader-friendly code, and rules for doing so. There's something comforting about approaching a while loop and knowing its not a leaky sieve, riddled with back doors, maybe even an exit( ) time bomb. But in the recursion world we want a minimum of two exits usually: when another round is called for versus when we've "hit bottom". Can we have it both ways? Conclusions: Lets not be too hasty with rules of thumb and: Lets keep the reader in mind when writing code. Just because the interpreter knows to compute the flow unambiguously, doesn't mean all ways of writing it are equally reader-friendly. What may seem a gratuitous gesture, an unnecessary flourish, may actually promote reader comprehension of your code, and that should be a goal as much as satisfying the interpreter. Kirby

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Re: [Edu-sig] Getting more involved with education and the PSF...
by Jeff Elkner Jan. 9, 2015

Jan. 9, 2015

Two questions: 1. Andre, what do I need to do to begin maintaining that page? 2. Is there anyone in this thread not on edu-sig? My next reply will go only to the list. On Thu, May 22, 2014 at 10:09 AM, Jessica Nickel <jessanickel(a)gmail.com> wrote: > Sounds like a plan. I would be happy to talk with Selena about the work to > bridge the gap between k-12 educators and Python programmers. I was a k-12 > teacher for 10 years (music) and I have been working in schools with my > program to teach python coding to kids for the past year and a half, so I do > have some experience in that area. > > > > > On Thu, May 22, 2014 at 10:02 AM, Jeff Elkner <jeff(a)elkner.net> wrote: >> >> Great! So it seems we have two short term goals: >> >> 1. Get someone to agree to maintain the website (I'm volunteering if >> there isn't anyone else chomping at the bit to do it). >> 2. Reach out to Selena Deckelman to help her with her efforts to >> bridge the gap between developers and K-12 teachers (a noble goal >> indeed!). >> >> Do we agree that edu-sig is the sensible place to hold this conversation? >> >> If we do, can we ask Selena to join the list if she is not already >> there? I'll also encourage folks like Lee Harr (cc'd here), the >> creator of the wonderful Pynguin environment >> (https://code.google.com/p/pynguin/) to join the list and the >> discussion. >> >> On Thu, May 22, 2014 at 8:01 AM, Naomi Ceder <naomi.ceder(a)gmail.com> >> wrote: >> > One point of info I can add - the person you're thinking of running for >> > PSF >> > board is Selena Deckelman, who was on Nate's panel at the edu summit. >> > She's >> > been very into bridging the gap between developers and K-12 teachers. >> > >> > Naomi > >

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Re: [Edu-sig] Getting more involved with education and the PSF...
by Chalmer Lowe July 29, 2014

July 29, 2014

It has taken a while, but I am finally getting settled into my new job and my new home, after a major relocation from the east coast to the pacific. I am now in a much better position to pick up this conversation and start moving forward with next year's Python Education Summit and working with the community to advance python education. I still have much to do to get the house fully habitable for the family, so don't expect any mad dashes right off the bat, but I certainly want to re-energize the conversation, make plans and begin execution. chalmer On Fri, May 23, 2014 at 4:15 PM, kirby urner <kirby.urner(a)gmail.com> wrote: > > I agree, not a problem at all, to include a full spectrum of outreach / > initiatives, > to K-12 (or the equivalent in other namespaces / systems) and beyond. > > In terms of the website, I think the edu-sig home page is a good place to > start: > https://www.python.org/community/sigs/current/edu-sig > > I notice when I'm at the maillist info page and click on edu-sig home page, > prominent at the top, I do NOT actually go to the above page, but to a > SIGs-in-general page: > > https://mail.python.org/mailman/listinfo/edu-sig > ---> https://www.python.org/community/sigs > > This is clearly broken, and a test of our new administrative muscles would > be > to get that fixed, I would think. > > On the home page itself I find at least one dead end link, e.g. under > Miscellaneous > > Software Carpentry <http://swc.scipy.org/> by Greg Wilson is a course on > software development > skills for scientists and engineers. > > That's not working at all. Maybe it just moved? > > Kirby > > > > On Fri, May 23, 2014 at 6:43 PM, Jeff Elkner <jeff(a)elkner.net> wrote: > >> Which has not been a problem at all. Think of the big involvement >> from the RIT folks in this year's PES. It's a meritocracy, after all. >> The volunteers who step forward determine what gets done. >> >> On Fri, May 23, 2014 at 4:27 PM, Jessica Nickel <jessanickel(a)gmail.com> >> wrote: >> > Kirby, >> > >> > I agree, and think there definitely needs to be a focus on both college >> and >> > community-based education outreach as well. >> > >> > >> > On Fri, May 23, 2014 at 4:26 PM, kirby urner <kirby.urner(a)gmail.com> >> wrote: >> >> >> >> >> >> Sounds good to me, as long as we're clear that "promoting Python in >> >> education" is in no way limited to K-12. I'm a full time teacher of >> Python >> >> to adults and like to think edu-sig is the right venue for my kind of >> >> chatter as well. So far, I've felt that way. K-12 is important and >> >> welcome, but not the whole show. >> >> >> >> Kirby >> >> >

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EuroPython
by Fernando Masanori Ashikaga July 21, 2014

July 21, 2014

Any person in this group is at EuroPython Berlin to exchange ideas about education? I am a CS professor at a public university in Sao Paulo State at Brazil and have a MOOC for teaching programming. PS.: MOOC == Massive Open Online Course

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Python Algorithm Visualizations done in browser
by Jurgis Pralgauskis July 10, 2014

July 10, 2014

http://pyalgoviz.appspot.com/ - nice idea :) -- Jurgis Pralgauskis tel: 8-616 77613; Don't worry, be happy and make things better ;) http://galvosukykla.lt

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Python is now the most popular language at top U.S. universities
by Philip Guo July 8, 2014

July 8, 2014

Here's something I cooked up last week. Feel free to spread the word to relevant colleagues, and I welcome any suggestions or bug fixes: https://news.ycombinator.com/item?id=8001337 Thanks, Philip

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algebra -> digital math (Python friendly)
by Kirby Urner July 2, 2014

July 2, 2014

I go into quite a bit of detail in this thread at the Math Forum, regarding what I think an Algebra course leading up to a digital math track might look like. http://mathforum.org/kb/thread.jspa?threadID=2637672 This is looking at what we might call "high school math" but I'd also bill it as an adult refresher or just adult friendly -- obviously given I'm in a commercial business-oriented adult-serving market niche myself these days and wouldn't wanna deny myself access to my own best thinking. ;-D However, much that I mention in this thread has been field tested with tween and teens over the years (Saturday Academy etc.). VPython has proved a real boon. Note: per earlier posts, Oregon is one of those states where for-math-credit courses like this have been authorized by law i.e. we don't have to call it a "computer club" and expect extra-curricular commitments. This is STEM-ready mathematics. Kirby

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