Mailman 3 February 2014 - Edu-sig

a short essay about programming
by kirby urner 08 Dec '22

08 Dec '22

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] RurPLE-NG is nice
by Jurgis Pralgauskis 05 Apr '14

05 Apr '14

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 :)

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Easy Web Environment to post pupils Python Creations
by Philip Bagge 01 Apr '14

01 Apr '14

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

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edu-sig web page
by kirby urner 22 Feb '14

22 Feb '14

As a former author / maintainer of the edu-sig web page and frequent visitor thereto, I have (a) welcomed the new beta website and (b) sent some feedback to the effect that: (i) opening first link / mention of this edu-sig maillist gets "permission denied" (ii) opening last link / mention of this edu-sig maillist gets full listing of all SIGs I have high hopes both glitches will be fixed in short order and wanted to document my actions here so we don't all send the same feedback. On the other hand, maybe that'd help improve the infrastructure? Let us wait and see. Good job on that new Python.org website eh? Kirby

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Re: [Edu-sig] Looking for a course syllabus exemplars for a high school year-long course in Python/Javascript
by Litvin 22 Feb '14

22 Feb '14

Roberto, Thank you for recommending our Math and Python book, but your amazon link is to the old edition. The current edition is at http://www.amazon.com/Mathematics-Digital-Age-Programming-Python/dp/0982477…, also available at www.skylit.com. Gary Litvin At 04:47 AM 2/20/2014, roberto wrote: >Hi Clint, >I was in your very situation in the past, and these are resources I >consider good: >- ><http://www.amazon.com/Mathematics-Digital-Age-Programming-Python/dp/0972705…>http://www.amazon.com/Mathematics-Digital-Age-Programming-Python/dp/0972705… >- http://inventwithpython.com/ >- <https://www.udacity.com/course/cs101>https://www.udacity.com/course/cs101 > > >According to the level of your students, and yours as well, you >might be more comfortable with one or more of the above mentioned. >I regularly run robotics after-school courses but I've never found >extremely helpful Python on NXT, for a number of technical glitches on it. >I prefer to focus on the learning way more than on the technical >aspects of the business. > >Hope this helps! >Have a great day. >Roberto. > > > > >On Wed, Feb 19, 2014 at 11:14 PM, Clint Johns ><<mailto:clint.m.johns@gmail.com>clint.m.johns(a)gmail.com> wrote: >Greetings Python community, > >I have been asked to create an introduction to programming course, >with an emphasis on Python and JavaScript, for this upcoming school year. > >My knowledge of Python is beginning/intermediate, but I am willing >to learn in order to make this a viable course. I am interested in >interfacing with LEGO NXT and EV3 robotics kits, and possibly >designing some games. > >If any of you can point me to some resources, it would be of great >help, and I would be extremely thankful. > >Continued success in all you do, > >Clint Johns >computer science teacher >San Francisco Bay Area, CA > >_______________________________________________ >Edu-sig mailing list ><mailto:Edu-sig@python.org>Edu-sig(a)python.org >https://mail.python.org/mailman/listinfo/edu-sig > > > > >-- >Roberto >_______________________________________________ >Edu-sig mailing list >Edu-sig(a)python.org >https://mail.python.org/mailman/listinfo/edu-sig

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Looking for a course syllabus exemplars for a high school year-long course in Python/Javascript
by Peter Beens 20 Feb '14

20 Feb '14

I'm using CS Circles in my 11th grade CS class. http://cscircles.cemc.uwaterloo.ca/ Students can set you up as their "guru" so you can monitor their progress and they can communicate with you when they are stuck on something. It's excellent, IMO. -Peter On Thu, Feb 20, 2014 at 6:00 AM, <edu-sig-request(a)python.org> wrote: > ---------- Forwarded message ---------- > From: Clint Johns <clint.m.johns(a)gmail.com> > To: "edu-sig(a)python.org" <edu-sig(a)python.org> > Cc: > Date: Wed, 19 Feb 2014 14:14:11 -0800 > Subject: [Edu-sig] Looking for a course syllabus exemplars for a high > school year-long course in Python/Javascript > Greetings Python community, > > I have been asked to create an introduction to programming course, with an > emphasis on Python and JavaScript, for this upcoming school year. > > My knowledge of Python is beginning/intermediate, but I am willing to > learn in order to make this a viable course. I am interested in interfacing > with LEGO NXT and EV3 robotics kits, and possibly designing some games. > > If any of you can point me to some resources, it would be of great help, > and I would be extremely thankful. > > Continued success in all you do, > > Clint Johns > computer science teacher > San Francisco Bay Area, CA > > > ---------- Forwarded message ---------- > From: roberto <roberto03(a)gmail.com> > To: Clint Johns <clint.m.johns(a)gmail.com> > Cc: "edu-sig(a)python.org" <edu-sig(a)python.org> > Date: Thu, 20 Feb 2014 10:47:18 +0100 > Subject: Re: [Edu-sig] Looking for a course syllabus exemplars for a high > school year-long course in Python/Javascript > Hi Clint, > I was in your very situation in the past, and these are resources I > consider good: > - > http://www.amazon.com/Mathematics-Digital-Age-Programming-Python/dp/0972705… > - http://inventwithpython.com/ > - https://www.udacity.com/course/cs101 > > > According to the level of your students, and yours as well, you might be > more comfortable with one or more of the above mentioned. > I regularly run robotics after-school courses but I've never found > extremely helpful Python on NXT, for a number of technical glitches on it. > I prefer to focus on the learning way more than on the technical aspects > of the business. > > Hope this helps! > Have a great day. > Roberto. >

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Looking for a course syllabus exemplars for a high school year-long course in Python/Javascript
by Clint Johns 20 Feb '14

20 Feb '14

Greetings Python community, I have been asked to create an introduction to programming course, with an emphasis on Python and JavaScript, for this upcoming school year. My knowledge of Python is beginning/intermediate, but I am willing to learn in order to make this a viable course. I am interested in interfacing with LEGO NXT and EV3 robotics kits, and possibly designing some games. If any of you can point me to some resources, it would be of great help, and I would be extremely thankful. Continued success in all you do, Clint Johns computer science teacher San Francisco Bay Area, CA

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some Pythonic Math for "code scouts"
by kirby urner 15 Feb '14

15 Feb '14

""" More ActiveMath... by K. Urner (c) MIT License 4dsolutions.net/ocn : Oregon Curriculum Network Merit badge activity: study the Method Resolution Order defined below and make a drawing of the inheritance tree, with object at the top and ScoutManual at the bottom. """ class Cove: def wheresWaldo(self): return "Waldo is in a Cove" class Island: def wheresWaldo(self): return "Waldo is on an Island" class CampA(Cove): pass class CampB(Cove): pass class CampC(Island): pass class TentQ(CampA, CampB): pass class TentR(CampC): pass class BaseCamp(CampA): pass class HappyCamper(TentQ, TentR): pass class ScoutManual(BaseCamp, HappyCamper): pass #========== for idx, parent in enumerate(ScoutManual.mro()): print ("{:>4}. {}".format(idx, parent)) m = ScoutManual() print(m.wheresWaldo())

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a segue from discrete math to calculus using Python
by Kirby Urner 04 Feb '14

04 Feb '14

""" Discrete math approach to Calculus This is what I imagine as a segue from discrete math to calc, using Python. We're using a tiny delta_x = h to compute values discretely, and then comparing those computed series with functions "at the limit" such as calculus would give us. It's the same segue we typically encounter using Sigma notation to introduce Riemann Sum notation in Algebra 2 today. All the assumptions are deliberately simplified: continuous functions in one variable. (c) MIT License, K. Urner, 4D Solutions, 2014 """ from math import log h = delta_x = 1e-2 # tiny delta class Integral: def __init__(self, func): self.func = func def __call__(self, a, b): if not a<=b: raise ValueError area = 0.0 x = a while x <= b: area += self.func(x) * delta_x x += delta_x return area class Derivative: def __init__(self, func): self.func = func def __call__(self, x): f = self.func return (f(x+h) - f(x-h)) / (2*h) def parabola(x): """Parabola""" return x * x # parabola def int_parabola(x): """Parabola""" return (x ** 3)/3 # integral of parabola def deriv_parabola(x): """Derivative of Parabolic function""" return 2*x # parabola def reciprocal(x): """Reciprocal""" return 1/x def int_reciprocal(x): """Integral of Reciprocal""" return log(x) # integral is Ln(x) def deriv_reciprocal(x): """Derivative of Reciprocal""" return -x**-2 def report(f, domain, limint, limderiv, C=0): integral_f = Integral(f) derivative_f = Derivative(f) print("=" * 30) print(f.__doc__, [(x,f(x)) for x in domain]) print() print("Approx Integral : ", ["({}, {:>5.2f})".format(x, integral_f(a=domain[0], b=x) + C) for x in domain]) print("Limit Integral : ", ["({}, {:>5.2f})".format(x, limint(x)) for x in domain]) print() print("Approx Derivative: ", ["({}, {:>5.2f})".format(x, derivative_f(x)) for x in domain]) print("Limit Derivative : ", ["({}, {:>5.2f})".format(x, limderiv(x)) for x in domain]) report(parabola, range(-10, 11), limint = int_parabola, limderiv = deriv_parabola, C = -334) # C = constant offset report(reciprocal, range(1, 11), limint = int_reciprocal, limderiv = deriv_reciprocal)

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