Mailman 3 November 2016 - 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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MineCraft with Python
by Jurgis Pralgauskis 04 Dec '22

04 Dec '22

Hi, intro: many kids like MineCraft :) probably you know/heared of MineCraft Pi https://www.raspberrypi.org/learning/getting-started-with-minecraft-pi/ But there seems to be Py for real MC http://coderdojotc.readthedocs.io/projects/python-minecraft/en/latest/ http://www.instructables.com/id/Python-coding-for-Minecraft/ PS.: a nice article (from js4MC world) https://github.com/walterhiggins/ScriptCraft/blob/master/docs/YoungPersonsG… -- Jurgis Pralgauskis tel: 8-616 77613; Don't worry, be happy and make things better ;) http://galvosukykla.lt

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turtle coordinates: Y increase downards - as in most graphics API?
by Jurgis Pralgauskis 02 Jul '18

02 Jul '18

Hi, usually in computer graphics Y is counted to increase downwards. I casn do it with: setworldcoordinates(0, 400, 600, 0) but then, "right(..)" turns to the left :/ I could swap: right, left = left, right but on errror I get a bit misleading message >>> right() Traceback (most recent call last): File "<pyshell#10>", line 1, in <module> right() TypeError: left() takes exactly 1 argument (0 given) I thought to make this hack for kids, so better clearer error msgs... Any Ideas? Thanks :) -- Jurgis Pralgauskis tel: 8-616 77613; Don't worry, be happy and make things better ;) http://galvosukykla.lt

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coding for high school math credit
by kirby urner 28 Nov '16

28 Nov '16

I'm back to researching high school courses that fulfill math requirements and that involve coding. In California the so-called A-G metric is used by UC (University of California) schools, to validate whether a given course of study qualifies as sufficient prep for admission to a UC campus. Here's an example: http://ucci.ucop.edu/GeometryComputerVisualizationSimulation.pdf It's context: http://ucci.ucop.edu/integrated-courses/a-g-table.html Some representative thinking behind such courses: https://edsource.org/2016/teaching-math-with-computer-programming-can-help-… i.e. your high school has no CS (computer science) but you want to including coding as a for-credit activity. Solution: bring coding into math courses. Math teachers get in-place professional development. Part of the motivation for offering such courses is equity i.e. providing a level playing field. Schools with a separate CS faculty tend to enjoy more affluent patronage. So what's another way to introduce coding that's not extra-curricular nor "elective" in the sense of not counting towards fulfilling requirements (e.g. A-G)? That's my focus: for-credit programming in high school without the necessity of branding the courses as CS, even if they include CS content. Regarding the above course, I'm glad to see emphasis on 3D printing. However when it comes to the fundamentals of polyhedrons and their dissections, I'd recommend doing a lot more with what are called A, B, T, E and S modules (specific 3D-printable shapes). >From example, 2 A modules, a left and right, plus either a left or right B, face-bond to form a "minimum tetrahedron" (MITE) that is also a space-filler. A = B = T = 1/24 in terms of volume, relative to a regular tetrahedron of 24 As (12 left and 12 right) as unit volume. Gluing may be a standard step in some 3D printing workflows: http://3dprinting.stackexchange.com/questions/54/what-is-the-best-way-to-co… Gluing MITEs into both cubes (volume 3) and rhombic dodecahedrons (volume 6) would be a next step. One could 3D print MITEs directly at this point, once the AAB dissection is well- understood. A- and B-modules also assemble the regular octahedron (volume 4).[1] We made a 24 A-module tetrahedron from paper at Winterhaven PPS back in the day (2006), during an all-sixth-grade assembly. http://mybizmo.blogspot.com/2006/02/sixth-grade-geometry.html 120 T-modules assemble into a rhombic triacontahedron (RT) of volume 5. Said RT radius is .9994 vs. the 1.0 radius of the 120 E-modules RT, a 5+ volumed RT that's scaled down by phi from a bigger RT in which our canonical icosahedron (volume 18.51...) is inscribed. Note that scaling 3D shapes, and the effect this has on area and volume is already part of the above course. I realize an excursion into American Literature for our alternative volumes-hierarchy might seem too obscure or exotic to some curriculum developers. I'd argue in contrast that such a course might thereby also count towards fulfilling UC B-pathway requirement (i.e. English / literature). Kirby [1] https://medium.com/@kirbyurner/american-literature-101-224489c26f19 (concentric hierarchy of polyhedrons in American literature)

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Re: [Edu-sig] Edu-sig Digest, Vol 160, Issue 9
by Peter Farrell 28 Nov '16

28 Nov '16

Thank you for providing links to all these resources! It's great to get the reference pages for JS and Python for the students I'm teaching. Peter Farrell Jobtrain Menlo Park, CA On Sat, Nov 26, 2016 at 5:55 PM, <edu-sig-request(a)python.org> wrote: > Send Edu-sig mailing list submissions to > edu-sig(a)python.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://mail.python.org/mailman/listinfo/edu-sig > or, via email, send a message with subject or body 'help' to > edu-sig-request(a)python.org > > You can reach the person managing the list at > edu-sig-owner(a)python.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Edu-sig digest..." > > > Today's Topics: > > 1. continuing with ES6 / Python comparison, other chatter > (kirby urner) > 2. Re: continuing with ES6 / Python comparison, other chatter > (Wes Turner) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 26 Nov 2016 17:32:46 -0800 > From: kirby urner <kirby.urner(a)gmail.com> > To: "edu-sig(a)python.org" <edu-sig(a)python.org> > Subject: [Edu-sig] continuing with ES6 / Python comparison, other > chatter > Message-ID: > <CAPJgG3TeE7_RTsk4sEcttKbRfDFs1wu4ts+ > W0ONdtr4ek0Pv6Q(a)mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > I just had shared "sushi train" (conveyor belt actually) with > a an IT chief with Everett School District, far north of here, > during which we discussed whether or not listservs (such > as edu-sig here) are on the decline across the board, having > been replaced with other social media by next generations > of Internet savvy. Do we know that for sure? > > For my part, I'm sure it depends on the subculture. I'm on > a very active listserv around csound, the music synth > language and engine, several posts a day. I'm sure sci.math > is as frantic as ever. > > nbviewer seems to time out quite a bit and I don't think it's > just me. Does the site get overloaded? > > I'm somewhat more likely than not to link directly to the > Github version i.e. the raw source, as here: > > https://github.com/4dsolutions/Python5/blob/master/Comparing%20JavaScript% > 20with%20Python.ipynb > > Shortened: https://goo.gl/jUqIwA > > ...versus feeding the latter through nbviewer. However > the latter does a more thorough job in many cases, so > I find it's worth it when it works. > > The above Notebook was just now lengthened with a > new comparison of ES6 and Python3 function calls. > > Question: will nbviewer accept a shortened URL as > input? > > Answer: no, but you're free to shorten the "nbviewer > + Github URL" combo naturally: https://goo.gl/HtM0NR > > Did you know ES6 is the first edition of JavaScript > wherein what we Pythonistas call default named > parameters and sequence parameters were first > acquired? > > In the above Notebook I extend to another example > showing these features in both, comparing two recipe() > functions. > > One could say Python has two "rest parameters", one > for "positionals," the others for "named". > > Perhaps in Python "keyword parameter" is a little more > correct than "named parameter" as the latter implies > use of = (naming) to give a default value, whereas > as shown in the example, one may have unnamed > parameters to the right of a sequence parameter, > that as a consequence are only reachable with > named arguments. > > Les (the above IT chief), is very familiar with the > Chromebook scene around public schooling in the > state just north of Oregon. I'm likely to venture into > that space pretty soon, as a Portland-based trainer. > > This will be a day job so I'm hopeful I'll be continuing > with the evening gig as "radio show" broadcaster > (a zoom.us-based tele-class). > > Speaking of which, I've been dropping in on some > of Trey Hunners chat sessions after the fact (I've > yet to make it to a live showing). I learned quite > a bit about duck typing in connection abc types > such as Sequence, thanks to this video: > > https://www.crowdcast.io/e/duck-typing > <http://treyhunner.us12.list-manage.com/track/click?u= > cdbc9ae7bf54c3dff2773ea2d&id=377dc1d5ad&e=16760d8b0b> > > I'm guessing more people learn about such free > resources from Twitterverse than from listservs these > days, but I don't have hard data. > > I wonder if Python.org keeps any stats on gross > subscriber numbers, posting rates etc. within its > vast Mailman empire: > > https://mail.python.org/mailman/listinfo > > Kirby >

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Python + JS == more than their sum()
by kirby urner 28 Nov '16

28 Nov '16

I'm continuing to advance the notion, in Medium comments and elsewhere, that learning one computer language at a time may be less efficient than tackling two or more, but with a "main one" front burner. [1] I credit the LEX Institute for this idea.[2] The theory being: contrasts and comparisons help concepts stick, whereas just one example (of a language, human or computer) provides less traction, a slipperier slope. Like learning the J language (jsoftware.com) even a little helps one realize how different languages can be, bringing Python into sharper relief against a background. But J (of APL heritage) might be too exotic as a #2, why not do JavaScript? Python + JS could be as common as HTML + CSS. That's a little self serving as a common bootcamp design if JS front end, Python back end. Our PDX Code Guild in Portland takes that tack. The curriculum, then, would continually bring them together to discuss their similarities and differences. Either one could be foreground first, with the other as background, but we'd do a lot of jumping back and forth (and not just with JSON :-D). A breakthrough realization I had earlier today was that Jupyter Notebooks already gives me a JavaScript interpreter, even when my main kernel is Python 3. %%javascript at the top of any cell creates a node-like experience, and I'm able to write ES6 (JavaScript) with classes, arrow functions and everything. It feels a lot like using node --harmony testfile.js on cloud9 (another learning platform I visit). Here's an example, of a Jupyter Notebook running through nbviewer, with both Python and JS code cells. The point is to show off the similarities. https://goo.gl/nj9RPO Kirby Useful tools: http://codepen.io/ http://jsbin.com/ [1] https://goo.gl/U4Yx6l (comment on one of Quincy Larson's, about which language to learn first) [2] 'Who Is Fourier?' (one of its pubs) appears way back in edu-sig. Jason Cunliff and I met and talked about it in New York that time. Here's one of Jason's from 2002: https://mail.python.org/pipermail/edu-sig/2002-September/002255.html

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continuing with ES6 / Python comparison, other chatter
by kirby urner 27 Nov '16

27 Nov '16

I just had shared "sushi train" (conveyor belt actually) with a an IT chief with Everett School District, far north of here, during which we discussed whether or not listservs (such as edu-sig here) are on the decline across the board, having been replaced with other social media by next generations of Internet savvy. Do we know that for sure? For my part, I'm sure it depends on the subculture. I'm on a very active listserv around csound, the music synth language and engine, several posts a day. I'm sure sci.math is as frantic as ever. nbviewer seems to time out quite a bit and I don't think it's just me. Does the site get overloaded? I'm somewhat more likely than not to link directly to the Github version i.e. the raw source, as here: https://github.com/4dsolutions/Python5/blob/master/Comparing%20JavaScript%2… Shortened: https://goo.gl/jUqIwA ...versus feeding the latter through nbviewer. However the latter does a more thorough job in many cases, so I find it's worth it when it works. The above Notebook was just now lengthened with a new comparison of ES6 and Python3 function calls. Question: will nbviewer accept a shortened URL as input? Answer: no, but you're free to shorten the "nbviewer + Github URL" combo naturally: https://goo.gl/HtM0NR Did you know ES6 is the first edition of JavaScript wherein what we Pythonistas call default named parameters and sequence parameters were first acquired? In the above Notebook I extend to another example showing these features in both, comparing two recipe() functions. One could say Python has two "rest parameters", one for "positionals," the others for "named". Perhaps in Python "keyword parameter" is a little more correct than "named parameter" as the latter implies use of = (naming) to give a default value, whereas as shown in the example, one may have unnamed parameters to the right of a sequence parameter, that as a consequence are only reachable with named arguments. Les (the above IT chief), is very familiar with the Chromebook scene around public schooling in the state just north of Oregon. I'm likely to venture into that space pretty soon, as a Portland-based trainer. This will be a day job so I'm hopeful I'll be continuing with the evening gig as "radio show" broadcaster (a zoom.us-based tele-class). Speaking of which, I've been dropping in on some of Trey Hunners chat sessions after the fact (I've yet to make it to a live showing). I learned quite a bit about duck typing in connection abc types such as Sequence, thanks to this video: https://www.crowdcast.io/e/duck-typing <http://treyhunner.us12.list-manage.com/track/click?u=cdbc9ae7bf54c3dff2773e…> I'm guessing more people learn about such free resources from Twitterverse than from listservs these days, but I don't have hard data. I wonder if Python.org keeps any stats on gross subscriber numbers, posting rates etc. within its vast Mailman empire: https://mail.python.org/mailman/listinfo Kirby

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Python + JS == more than their sum()
by kirby urner 22 Nov '16

22 Nov '16

Wow, thank you Kevin and Wes for some eye-opening contributions! I really welcome their mind-expanding potential and have been diving into demos and docs all morning. [1] In my course last night we looked at that Jupyter Notebook comparing ES6 and Python scripts [2] and I also showed them how Python may be used to write HTML + CSS for browser rendering.[3] Output: https://flic.kr/p/PjQ6Bg (screen shot). Some of my students are beginner programmers, with little to no programming background so we're really just going over the basics, but at the same time we need to tune in the ecosystem with is typically a combination of Python + HTML + CSS + JS + SQL + regex at least. I use sqlite3 module for the SQL part, re module for regex. What we have in these resources though is something even more ambitious, including the ability to compile Python to JS! Wow. You know what they say: JS is the assembly language of the web. Even developers using JS full stack use transpilers to go from future JS -> past JS (using Babel mostly). Future JS (from where we stand now) is what looks more Python-like than ever. My current mode of teaching is to have students install the Anaconda distro and then to extend the library with the requests and flask modules for exploring web stuff. Anaconda includes command line conda for using in place of pip, to get packages from a large web of repositories. Now I see conda lets me install mpld3 to my Mac with no issues. mackurner:~ kurner$ conda install mpld3 My teaching application is here: thekirbster.pythonanywhere.com Kirby [1] Kevin, http://pyeverywhere.org/docs/ 404s [2] https://github.com/4dsolutions/Python5/blob/master/Comparing%20JavaScript%2… (that's direct to Github -- nbviewer is having problems right now, no wait it's working again) https://goo.gl/nj9RPO (using nbviewer) renders the JS output whereas Github does not. [3] a chess board generator, just uses string substitution ala str.format( ) method, helps beginners see how HTML + CSS might be string output from a Python script on the server: # -*- coding: utf-8 -*- """ Created on Thu Nov 17 09:02:27 2016 https://flic.kr/p/PjQ6Bg (screen shot). @author: Kirby Urner Run the script and open the output .html file in any browser. """ from collections import namedtuple Piece = namedtuple('Piece', 'type color position unicode') black = [ Piece("Rook" , "black", [7,0], "♜"), Piece("Knight" , "black", [7,1], "♞"), Piece("Bishop" , "black", [7,2], "♝"), Piece("Queen" , "black", [7,3], "♛"), Piece("King" , "black", [7,4], "♚"), Piece("Bishop" , "black", [7,5], "♝"), Piece("Knight" , "black", [7,6], "♞"), Piece("Rook" , "black", [7,7], "♜") ] for c in range(8): black.append(Piece("Pawn", "black", [6,c], "♟")) white = [ Piece("Rook" , "white", [0,0], "♖"), Piece("Knight" , "white", [0,1], "♘"), Piece("Bishop" , "white", [0,2], "♗"), Piece("Queen" , "white", [0,3], "♕"), Piece("King" , "white", [0,4], "♔"), Piece("Bishop" , "white", [0,5], "♗"), Piece("Knight" , "white", [0,6], "♘"), Piece("Rook" , "white", [0,7], "♖") ] for c in range(8): white.append(Piece("Pawn", "white", [1,c], "♙")) the_board = \ """ <table> {white_royals} {white_pawns} {empty_cells} {black_pawns} {black_royals} </table>""" white_royals = "<tr>{}</tr>".format("".join( ["<td>{}</td>".format(piece.unicode) for piece in white[:8]])) white_pawns = "<tr>{}</tr>".format("".join( ["<td>{}</td>".format(piece.unicode) for piece in white[8:]])) black_royals = "<tr>{}</tr>".format("".join( ["<td>{}</td>".format(piece.unicode) for piece in black[:8]])) black_pawns = "<tr>{}</tr>".format("".join( ["<td>{}</td>".format(piece.unicode) for piece in black[8:]])) empty_cells = "" for row in range(4): empty_cells += "<tr>{}</tr>".format("".join( ["<td></td>" for _ in range(8)])) chess_board = the_board.format(white_royals = white_royals, white_pawns = white_pawns, empty_cells = empty_cells, black_royals = black_royals, black_pawns = black_pawns) the_page = \ """<!DOCTYPE html> <html> <head> <style> body { margin-left: 30px; font-size: 20px; } table { border: 1px solid black; border-collapse: collapse; border-color: black; } td { padding: 15px; border: 1px solid black; height: 20px; vertical-align: bottom; } tr:nth-child(even) td:nth-child(odd){ background-color: #FF8040; } tr:nth-child(odd) td:nth-child(even){ background-color: #FF8040; } td:hover { background-color: #FF0000 !important; border-color: blue; } </style> </head> <body> """ + \ chess_board \ + \ """ </body> </html> """ with open("chessboard02.html", "w") as f: f.write(the_page) print("Done!")

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interview with Kirby Urner (PyDev of the Week series)
by kirby urner 14 Nov '16

14 Nov '16

I'm sharing more biographical info so we keep getting to know one another better: http://www.blog.pythonlibrary.org/2016/11/14/pydev-of-the-week-kirby-urner/ My thanks to Mike Driscoll of Mouse vs. Python for putting this together. The article talks about my coming to Python thanks to my interest in geometry.[1] I don't go in to the specifics of that geometry in the interview, but have on edu-sig.[2] Kirby Urner Portland, Oregon [1] similar story as my friend the late Arthur Siegel, likewise crazy about geometry: http://www.4dsolutions.net/ocn/pygeo.html [2] and of course in my blogs e.g. just yesterday: http://mybizmo.blogspot.com/2016/11/planning-ahead.html

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