Mailman 3 January 2013 - 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

8 17

Re: [Edu-sig] RurPLE-NG is nice
by Jurgis Pralgauskis April 5, 2014

April 5, 2014

Some updates: - separated Variables Watch and Output panes, to be seen simultaneusly - implemented Breakpoints :) - beta style Todo: - let enter arbitrary watch expressions http://ftp.akl.lt/users/jurgis/python/rurple-NG053.png http://ftp.akl.lt/users/jurgis/python/rurple-ng-dz0-SplitLogVars_and_Breakp… for windows one doesn't need to install python separately, just unzip and run :) http://ftp.akl.lt/users/jurgis/python/RURPLE-NG-0.53%20%5bindependent%20exe… ps.: RurPLE-NG uses py3 unicode_literals, with_statement, division, print_function so code is generally py3 compliant. when wxpy will work well with py3 it shouldn't be too hard to port fully... >> >> just wanted to mention, >> that http://dev.lshift.net/paul/rurple/ >> is a very nice and lightweit PLE. >> >> what I like most (compared to RurPLE) are: >> 1) variables watch list (if it had breakpoints, it would rock :)

2 3

Easy Web Environment to post pupils Python Creations
by Philip Bagge April 1, 2014

April 1, 2014

Dear Colleagues, My Y6 pupils (10-11 year olds) have been creating some simple text based linear adventures using Python. Does anyone know of a way we can play their adventures online? They are not very complicated. You can see the planning here. https://sites.google.com/site/pythoncodecouk/python-adventure Also as a new person to your forum does anyone know of an easy way to search you archives just in case someone has already answered this question. Thanks in advance for any help Phil Bagge -- Primary ICT Advanced Skills Teacher HCC Teacher & IT Manager http://code-it.co.uk

4 5

Python's keywords and functions convertor into native language for lowering entrance barrier
by Murat Jumashev Feb. 10, 2013

Feb. 10, 2013

Hi, My name is Murat, I am from Bishkek, Kyrgyz Republic (Central Asia). First off let me apologize if I chose a wrong mailing list (please, kindly point me a right mailing list to go). I am new to programming and I started from Python because it's very smooth and readable lang. But it would not be easy for me to start learning programming concepts without knowing basic English. What I want to ask is is it possible to create a (buffer/middleware) keywords and functions convertor-from-pythonese-English-to-pythonese-Kyrgyz (and vice-versa) so that students with poor/no English could start learning to code in their native language(s)? i.e. print / басуу, if / эгерде, else / болбосо, elif / же болбосо etc. I am impressed by the guy who have invented an arabic programming language in order to overcome a (natural) language barrier: http://killscreendaily.com/headlines/arabic-programming-language-middle-eas… But I think it's more rational to write a native-to-pythonese-convertor rather than inventing a new language from scratch. Can anyone tell me from where to start? Thank you.

4 5

Teaching Math with Python
by Dan Peirce Jan. 28, 2013

Jan. 28, 2013

I came across an old story at http://onlamp.com/pub/a/python/2000/10/04/pythonnews.html about Teaching Math with Python. Unfortunately the links are now broken. Is there more current information available? Any online publications?

4 3

PyGeo
by Kevin Jan. 26, 2013

Jan. 26, 2013

Hi folks, I'm new to python and super-excited about using it for all sorts of reasons including education (especially math education). I've been reading a great deal on the subject, and I discovered some of Kirby's resources at http://4dsolutions.net/ocn/cp4e.html which have been very helpful. I was especially intrigued by the very simple Euclid's algorithm that he showed in the python for math teachers videos at http://showmedo.com/videotutorials/series?name=JkD78HdCD I'm also very interested in VPython and PyGeo. I read a fair amount of background on PyGeo including the sad news of Arthur's passing in 2007. And I've searched the web for news on the current status of PyGeo since Arthur passed, and have found very little <http://osdir.com/ml/python.visualpython.user/2007-02/msg00013.html>. Can anyone give me any better insights on the state of the PyGeo code base? From http://pygeo.sourceforge.net/ it looks like the last revision to the PyGeo code base was 7 years ago, but perhaps someone here knows of more recent developments with PyGeo? With all the changes that have taken place since 2007, does anyone know if I should expect that PyGeo will still work ok with Python 2.7 or Python 3.2? Also, has anyone shown any interest in continuing to develop PyGeo? Although I'm very new and still have a lot to learn, Arthur sounds like he was a man after my own heart, and I suspect that I would enjoy trying to pick up his PyGeo work where he left off if nobody else has done so. I probably will not be able (skill-wise) to improve upon his work in the next year or so, but I can't help thinking it might be feasible for me after that. I'd welcome reading any thoughts on these or related issues via private email or public list follow-up. Thanks everyone. -Kevin

2 1

ApacheCon: it's about a lot more than Apache webserver
by kirby urner Jan. 24, 2013

Jan. 24, 2013

http://projects.apache.org/ (FYI) ---------- Forwarded message ---------- From: Steve Holden <steve(a)holdenweb.com> Date: Wed, Jan 23, 2013 at 3:03 PM Subject: Time to make a noise ... We'd appreciate your help in creating a little more buzz about ApacheCon NA. It turns out that another major West coast big data/cloud conference has been scheduled on exactly the same days as ApacheCon, reducing the anticipated effects of our marketing and PR efforts. On the plus side, this other conference is highly likely to sell out, and when it does the Apache community can be standing by with a welcoming smile on its face. So we may pick up late registrations. At the moment, however, numbers are lower than anticipated, which is where you come in. The really effective way to get the word out is via community channels. The life blood of any conference is the people who pay to go through the doors. The existing community members get a chance to meet old friends and work together. There will also be people who maybe work with your code every day but would not think of themselves as committer material (they probably think of existing committers are rock stars). So the people who know you by your professional reputation are exactly the people who might attend ApacheCon. If they know you are going, they are more likely to go. If you have blogs or other web presences and want to help publicize the conference, banner graphics are available at http://holdenweb.com/acna13gfx/ Please remind any relevant mailing lists you belong to that ApacheCon is coming (33 days to go at the time of writing) and that if they don't register soon they run the risk of losing the 30% discount we negotiated on the hotel room rate. Steve Holden steve(a)holdenweb.com +1 571 484 6266 @holdenweb -- Python classes (and much more) through the web http://oreillyschool.com/ Conferences and technical event management at http://theopenbastion.com/ Next event: ApacheCon NA 2013: Feb 26-28 http://na.apachecon.com/ Community events: Barcamp Feb 24 Hackathon Feb 25 Development Mar 1/2

1 0

Drs. Fotis Georgatos's MSc thesis
by Dan Peirce Jan. 24, 2013

Jan. 24, 2013

On the Page http://www.python.org/community/sigs/current/edu-sig/ Under Academic Papers there is a link to “Drs. Fotis Georgatos's MSc thesis, How applicable is Python as first computer language for teaching programming in a pre-university educational environment, from a teacher's point of view?” http://arxiv.org/ftp/arxiv/papers/0809/0809.1437.pdf On the third page of the thesis it says “Each word of this thesis is plagiarized. I have never generated a single word myself.” So is this a real thesis? Was he making a joke? Is the link supposed to be a Joke? I’m asking since I quoted it twice and then someone asked me the same question.

3 2

Free / Open MOOC with Open Materials
by Charles Severance Jan. 16, 2013

Jan. 16, 2013

Hi all, I just wanted to let you know about a very open Python MOOC I am doing over the next 10 weeks. It is a little different than other MOOCs in that everything is open and reusable/remix-able materials. It is based on my book "Python for Informatics: Exploring Information". It is derived from Alan Downey's + Jeff Elkner's Think Python book with a switch form a math-focus to more of a data-focus. I am doing an experiment where I am mixing 70 of my on-campus students with about 220 open-enrollment students in the same learning environment. I hope the things I am building like an auto-grader based on Brad Miller's Skulpt in browser Python environment can be helpful to other teachers. I figured I would let the edu-sig folks know about the course. http://online.dr-chuck.com/ http://www.pythonlearn.com/ Folks can still join the course until early February and I have a playground space that is always open for folks to watch lectures and play with the auto-grader. Comments welcome. Charles Severance University of Michigan http://www.dr-chuck.com/

1 0

Re: [Edu-sig] Easy Web Environment to post pupils Python Creations
by John Posner Jan. 16, 2013

Jan. 16, 2013

On 1/16/2013 6:00 AM, edu-sig-request(a)python.org wrote: > > My Y6 pupils (10-11 year olds) have been creating some simple text based > linear adventures using Python. > Does anyone know of a way we can play their adventures online? > They are not very complicated. > You can see the planning here. > https://sites.google.com/site/pythoncodecouk/python-adventure > Crunchy might help: http://showmedo.com/videotutorials/series?name=jBz4yv8Xg > Also as a new person to your forum does anyone know of an easy way to > search you archives just in case someone has already answered this question. > http://mail.python.org/pipermail/edu-sig/

2 1