Mailman 3 June 2017 - 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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MineCraft with Python
by Jurgis Pralgauskis Dec. 4, 2022

Dec. 4, 2022

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 July 2, 2018

July 2, 2018

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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Mathematically Backward States
by Peter Farrell July 17, 2017

July 17, 2017

> > > You're in California right? A backward state by most accounts. > I'd be offended but everything I've experienced here on the San Francisco peninsula supports your claim. We have a huge STEM and Maker movement but the "M" is only making the odd polyhedron (yes, Kirby they're odd, except for the even ones) or eating pie once a year. My friend's Catholic school is very open to STEM stuff but perhaps only because it's an elementary school. Once the Peninsula kid is in high school the worrying begins and anything that's not on the SATs is seen as suspect. I'm not exaggerating. Another friend of mine was a math teacher, and a fairly traditional, non-techy one at a Catholic high school nearby until this year. He had the audacity to use "non-mathematical language" (he made some joke about "parent" and "child" functions) and he brought in a meat grinder to help the students visualize function input and output. (I play it safe and only draw function machines on the whiteboard.) He lost his job in the middle of the school year, and a student at that school confirmed to me that teachers who explain things in a different way get fired. I jokingly emailed his ex-supervisor and asked about the job. She wrote back with a description that included words like "innovative" and she looked at my webpage (all Python and 3D graphics...) and thinks I should apply for the position! For all she knows, I could be Harry Freaking Potter and cover everything from the Babylonians up to Emmy Noether and still fit in my silly techy stuff. Living in Silicon Valley I thought we'd have a more progressive math curriculum but the techy stuff is only for after-school clubs and summer tech camps. It makes sense, since Americans think we do everything the right way, and especially in such a rich area as Silicon Valley, we're damn near perfect so why change anything? Maybe folks in the Central Valley or beyond are more open minded. Peter Farrell

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Re: [Edu-sig] PyCharm Edu with Stepik
by Andrew Harrington June 25, 2017

June 25, 2017

I'd rather use http://interactivepython.org/runestone/static/thinkcspy/index.html for a gentle introduction all in one place, and when we want to do more elaborate varied projects, just use PyCharm community edition. Dr. Andrew N. Harrington Computer Science Department Graduate Program Director gpd(a)cs.luc.edu Loyola University Chicago 529 Lewis Towers, 111 E. Pearson St. (Downtown) 417 Cudahy Science Hall (Rogers Park campus) http://www.cs.luc.edu/~anh Phone: 312-915-7982 Fax: 312-915-7998 aharrin(a)luc.edu (as professor, not gpd role) On Sat, Jun 24, 2017 at 11:09 AM, Jurgis Pralgauskis < jurgis.pralgauskis(a)gmail.com> wrote: > Hi, > > anybody else tried/uses Pycharm Edu? > I like, that it proposes some simple integration with learning management > in cloud > https://blog.jetbrains.com/pycharm/2017/06/integration-with- > stepik-for-educators/ > > -- > Jurgis Pralgauskis > tel: 8-616 77613; > Don't worry, be happy and make things better ;) > http://galvosukykla.lt >

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Re: [Edu-sig] Edu-sig Digest, Vol 167, Issue 15
by Harry Riley June 24, 2017

June 24, 2017

On Jun 24, 2017 12:49, <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. Re: Exhibit: Session 2 of 10, a Python training (kirby urner) 2. PyCharm Edu with Stepik (Jurgis Pralgauskis) 3. Re: PyCharm Edu with Stepik (Andrew Harrington) 4. Re: Exhibit: Session 2 of 10, a Python training (Carl Karsten) ---------------------------------------------------------------------- Message: 1 Date: Sat, 24 Jun 2017 09:04:52 -0700 From: kirby urner <kirby.urner(a)gmail.com> To: Carl Karsten <carl(a)nextdayvideo.com> Cc: "edu-sig(a)python.org" <edu-sig(a)python.org> Subject: Re: [Edu-sig] Exhibit: Session 2 of 10, a Python training Message-ID: <CAPJgG3RvpYwfeP3sM=mdefyg0+zyjdxqaO+Hgun5mqrtujpCLg(a)mail.gmail.com> Content-Type: text/plain; charset="utf-8" On Fri, Jun 23, 2017 at 6:32 PM, Carl Karsten <carl(a)nextdayvideo.com> wrote: > > On Fri, Jun 23, 2017 at 3:12 AM, kirby urner <kirby.urner(a)gmail.com> > wrote: > >> Looping with for >> more string formatting >> > > > Kerby, I am curious about the pedagogy of introducing two distinct > concepts at the same time like that. Care to elaborate? > I introduce string formatting with {placeholders} early in the training, and then keep using that. I also use the keywords list (keyword.kwlist) for raw material, when introducing for loops. So something like this: from keyword import kwlist for word in kwlist: if word.islower(): # showing how conditionals work print("Lowercase keyword: | {:20} |".format(word)) The format method is a good stand-in for callables in general in that we can start looking at positional versus named arguments, * and ** as argument exploders etc. So yeah, my technique is to keep introducing new concepts (e.g. for loop) while continuing to use those looked at so far (e.g. print formatting). Kind of like a juggling act, where one keeps introducing more balls. Kirby Kirby

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Exhibit: Session 2 of 10, a Python training
by kirby urner June 24, 2017

June 24, 2017

# -*- coding: utf-8 -*- """ Created on Thurs June 22, 2017 Course: PYT-PR (Saisoft.net) Instructor: Kirby Urner kirby.urner(a)gmail.com Audio Check (6:15 PM PDT) Introduction What's an Object? Types we've seen briefly: int float string datetime list... ... lets keep adding to that python_types.py Mapping versus Sequence: dict & set Looping with for more string formatting Lab 1: In file elements.py, create named tuples for the first 10 elements of Periodic Table. Need at least: protons, abbreviation, long name. Print all elements in a for loop. New types: range enumerate collections.namedtuple collections.Counter Lab 2: create a dict with abbreviations as keys, for your elements, in elements.py Worth watching (some other time): https://youtu.be/lyDLAutA88s David Beazley | Keynote: Built in Super Heroes Objects: What is an API? Internal state Dot Notation (going within) Review / new: sys module and sys.path os module. elements.py is a module too Immutable versus Mutable: tuple versus list, what's the difference? Callable verus not Callable does it need "a mouth" (with or without arguments?) Lab3: create more formatted printing for elements.py (elements_lab3.py) Summary of Session 02 """ >From the shared Google drive lesson folder: # -*- coding: utf-8 -*- """ Created on Thu Jul 7 19:36:12 2016 @author: kurner LAB: Create a namedtuple to represent an element. Use the Periodic Table to define 10 namedtuples corresponding to the first 10 elements. Such as Hydrogen, Helium and so on. Need at least: protons, abbreviation (1 or 2 letters), long name Example: Employee = namedtuple("Job Holder", "name age title") Hint: "{:10} | {:10} | {:10}".format(4.5, 5.8, 9.0) """ from collections import namedtuple Element = namedtuple("Atom", "protons abbrev long_name mass") # FIRST 10 ELEMENTS FROM PERIODIC TABLE all_elements = dict() all_elements["H"] = Element(1, "H", "Hydrogen", 1.00794) all_elements["He"] = Element(2, "He", "Helium", 4.002602) all_elements["Li"] = Element(3, "Li", "Lithium", 6.941) all_elements["Be"] = Element(4, "Be", "Beryllium", 9.012182) all_elements["B"] = Element(5, "B", "Boron", 10.811) all_elements["C"] = Element(6, "C", "Carbon", 12.0107) all_elements["N"] = Element(7, "N", "Nitrogen", 14.0067) all_elements["O"] = Element(8, "O", "Oxygen", 15.9994) all_elements["F"] = Element(9, "F", "Fluorine", 18.998403) all_elements["Ne"] = Element(10, "Ne", "Neon", 20.1797) all_elements["Na"] = Element(11, "Na", "Sodium", 22.98976928) all_elements["Mg"] = Element(12, "Mg", "Magnesium", 24.4050) all_elements["Al"] = Element(13, "Al", "Aluminum", 26.8815386) all_elements["Si"] = Element(14, "Si", "Silicon", 28.0855) all_elements["P"] = Element(15, "P", "Phosphorous", 30.973762) all_elements["S"] = Element(16, "S", "Sulfur", 32.065) all_elements["Cl"] = Element(17, "Cl", "Chlorine", 35.453) all_elements["Ar"] = Element(18, "Ar", "Argon", 39.948) all_elements["K"] = Element(19, "K", "Potassium", 39.0983) all_elements["Ca"] = Element(20, "Ca", "Calcium", 40.078) all_elements["Sc"] = Element(21, "Sc", "Scandium", 44.955912) ordered_elements = \ ["H", "He", "Li", "Be", "B", "C", "N", "O", "F", "Ne", "Na", "Mg", "Al", "Si", "P", "S", "Cl", "Ar", "K", "Ca", "Sc"] print(" PERIODIC TABLE") print() print(" Protons Abbrev Mass") print("-" * 50) for atom in ordered_elements: the_atom = all_elements[atom] print("{0:>10} | {1:^10} | {2:12.8} |".format(the_atom.protons, the_atom.abbrev, the_atom.mass))

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PyCharm Edu with Stepik
by Jurgis Pralgauskis June 24, 2017

June 24, 2017

Hi, anybody else tried/uses Pycharm Edu? I like, that it proposes some simple integration with learning management in cloud https://blog.jetbrains.com/pycharm/2017/06/integration- with-stepik-for-educators/ -- Jurgis Pralgauskis tel: 8-616 77613; Don't worry, be happy and make things better ;) http://galvosukykla.lt

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Fwd: RFC: Terms of use for a new Git hosting platform for educational projects
by Dominik George June 20, 2017

June 20, 2017

Hi everybody, we, Teckids e.V. [0], a German youth organisation around free software, are in the process of making some of our internal systems and services public for use by everyone contributing to or running educational projects, or using free software in education. The two major services will be Edugit, a code hosting platform running GitLab, and a remote desktop system that can be used to use and develop free software for education (RDP and browser-based access to a full Debian desktop). Edugit is, in our view, very necessary because all code hosting platforms, like GitHub and GitLab.com, have terms of use that not only may be bad for privacy or freedom [1], but above all lock out an important group of contributors. Mainly because they are hosted in the US where COPPA applies, all individuals underthe age of 13 are denied access. However, we believe that people of all ages should be able to contribute in education. Therefore, we have started Edugit for our projects, and are now one footstep away from making it public. Please try to *not* discuss the usefulness or what you belive in this thread - please contact us directly if you have concerns. Today, we want to ask for your comments on our drafts for Terms of Use. We tried to keep them as short and easy to understand as possible, while imposing limitations only on the range of use of the platforms. Please also do not provide legal advice - the terms will be reviewed by a lawyer in addition to this RFC ☺. Here are the drafts in German and English: https://www.teckids.org/cgit/verein.git/plain/intern/tou_de.txt https://www.teckids.org/cgit/verein.git/plain/intern/tou_en.txt The drafts were created by people who are concerned by it most - a group of contributors from 10 to 27 years of age (children are involved in everything we do, fwiw). We ask for all feedback, ranging from "cool, ack, go on" to all your concerns (content-wise) and ideas. But please think before you post - please do not flood your community's mailing list with "+1", only post there if you want your post discussed. But please always keep me <dominik.george(a)teckids.org> in the recipients, as I am not subscribed to all lists this is posted to. Looking forward to your feedback, Nik P.S.: If you can - and want to - support the projects financially, please see https://www.teckids.org/spenden.htm (German) or just ask. We always need it ☺! [0]: https://www.teckids.org/ [1]: https://www.gnu.org/software/repo-criteria-evaluation.html -- Dominik George (1. Vorstandsvorsitzender, pädagogischer Leiter) Teckids e.V. - Erkunden, Entdecken, Erfinden. https://www.teckids.org/

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a simple api for json data
by kirby urner June 18, 2017

June 18, 2017

[1] also a missing footnote from my previous post: https://github.com/4dsolutions/Python5/blob/master/py_async_get_chemicals.py Feel free to hit against my $5/mo Hacker account with pythonAnywhere for teaching your students how to go against an API with urllib or requests or whatever e.g.: url = "http://thekirbster.pythonanywhere.com/api/elements?elem=Fe" with urllib.request.urlopen(url) as response: html = response.read() html Out[11]: b'[26, "Fe", "Iron", 55.8452, "transition metal", 1493462392, "KTU"]' The API itself is pretty simple and documented on the home page: http://thekirbster.pythonanywhere.com Feel free to ask me questions on this thread on edu-sig. I'm not selling you a product, just yakking about a free service. The complete source code for this tiny Flask application is also visible on Github. I use this for teaching my courses. Kirby

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