Mailman 3 July 2018 - 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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Editors/IDEs for teaching
by Andre Roberge 14 Sep '18

14 Sep '18

Hi everyone, I'm compiling a list of available editors for Python designed specifically for teaching, with information about the primary targeted audiences and would welcome your comments and/or suggestions for additions or corrections. So far, I have Target audience (my own draft definition; feel free to improve upon this): * young learners (elementary and high school students) * hobbyists - beginners of all ages learning on their own * CS 100 course: elective course targeted at non CS (or even non STEM) students. The focus is more on concepts, using Python as the practical tool to learn these concepts, rather than learning the Pythonic idioms or learning the effectiveness of various algorithms. For example, list comprehensions would likely not be covered in such a course as it does not add anything conceptually to an explicit for loop. * CS 101 course: core course in CS meant as a requirement for future courses. Some pythonic idioms and details about algorithms would likely be covered. Editors / IDEs : * IDLE: included with Python. Intended for everyone. * Mu (https://codewith.mu/). Primarily intended for young learners and hobbyists. * Thonny. (http://thonny.org/) I am guessing that it is primarily intended for CS 101. * Wing 101 (https://wingware.com/downloads/wingide-101) Primarily intended for CS 101. * PyCharm Edu (https://www.jetbrains.com/pycharm-edu/) Primarily intended for CS 101. I am not looking for web-based solutions [otherwise, I would have had included Reeborg's World ;-)] and do not want to include obsolete or no longer maintained software (like rur-ple, the precursor to Reeborg's World.) Best, André

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Python in Highschool (exams)
by Aidis Stukas 01 Aug '18

01 Aug '18

Are there any countries that teach Python in high school. Also, is it allowed to use Python in programming/informatics exam, if your country has one? -- Aidis Stukas

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Python for Microprocessors
by kirby urner 30 Jul '18

30 Jul '18

I'm just now perusing Steve Holden's slides for the first time, in PDF format, regarding the state of the art when it comes to Pythonic hardware (e.g. Micro:bit): https://github.com/holdenweb/PyConIE2017/blob/master/MicroPythonEcosystem.p… I find this illuminating. Steve has a long fascination with hardware programming. Also, I'm just putting some finishing touches on a Medium piece (unrestricted) advertising the capabilities of the Raspberry Pi platform (not Python specific, but certainly Python-linked): https://medium.com/@kirbyurner/summer-camp-computing-some-fun-in-the-sun-95… (the top picture shows a Pi Lab the same Steve Holden set up in Portland some years ago, helping to catalyze our little subculture). Kirby

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the state of Vpython
by kirby urner 20 Jul '18

20 Jul '18

edu-sig has a long history with Visual Python, going back to Pygeo (Arthur Siegel's project, pygeo.sourceforge.net/ ) any my own work with that package. What's the state of the art today? In a word: Glowscript. Here's a good example. I see dates on the source code suggesting the site is maintained and evolving. https://bphilhour.trinket.io/physics-through-glowscript-an-introductory-cou… Kirby

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learning by contributing to FLOSS (and pygame in specific)
by René Dudfield 18 Jul '18

18 Jul '18

Hello, I'm looking for a small group of 10-30 people who are interested in contributing to the pygame project as part of a class or user group meeting. Rather than a normal user group meeting or class, it could be: "contribute to an open source project". Be in touch!? Let's do it! :) *Why?* (teaching by helping people contribute to FLOSS projects.) Because you don't learn karate from a book. Builds social connections and skills. Portfolio, and evidence of talent. Sort of fun and different compared to a talks night at a user group. *Why pygame?* (rather than some other project) Because I want to do this with my pet project. It's sort of fun compared to some topics (better than watching paint dry at least). Because it's sort of well known project (millions of users). ... with almost zero full time or even part time developers (that's why it's called pygame zero). Because I will help before and during the class(es)/session(s), and have resources and issues prepared. *[hey! you could totally do this with your own pet projects too!]* *How will a gathering work?* *The goal*: At the end of the gathering, people will have learned how a FLOSS project is done, submitted a PR, and have a big thank you posted on the website. A session could run like this: 1. A short lightning talk can be done on what's happening by someone on how to write a unit test, and what is a github issue (slides can be made available). 2. A number of topics will be presented to choose from. These will be 'low hanging fruit' issues. Like, "write a test for a draw rectangle functions". 3. People will split off into small groups of 2-4 people. Each choosing an issue. Probably beginners and experts will be mixed together. 4. Project developers will be available via web chat (Discord) (or in person perhaps if it's where the developers live...). 5. results will be pasted into issues, and perhaps even pull requests made. 6. At the end one person from each group will show off what they've done and experienced to the group. (several short talks) [Hrmm... you may be thinking that this sort of sounds exactly like a Dojo (shout out to London Python Dojo) or mini conference sprint format(shout out to pypy!). Yop.) If anyone wants to do this with me please be in touch to get this going! I will announce when it's happening so people can drop by online too if they want. cheers,

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Re: [Edu-sig] False alarms?
by kirby urner 17 Jul '18

17 Jul '18

Hi Sergio -- Per this article, with so many states and no national curriculum (I don't advocate for one), it's tough to generalize about US schools: https://www.theatlantic.com/education/archive/2018/07/americas-schools/5644… Now, to generalize :-D The mathematics classroom was rarely also a computer lab. If the school has a computer lab, that's usually a separate facility and they learn business applications and typing, rarely much programming, until rather recently. Today, schools likely have Chromebooks in large charging cabinets on rollers. Fewer schools give out Chromebooks to each student but that's the trend, perhaps from 6th or 7th grade up. The mathematics curriculum has never integrated any programming as there's still that sense that programming takes years to learn and would be a huge detour. Those of us more familiar with the state of the art don't see it that way. You're right that Mathematica paved the way for a small subculture and I-Python, Sage, Jupyter Notebooks, SymPy do feature in some US schools, but very few. Rather than integrate mathematics and learning to code, the strong belief is we need to keep math and computer science separated, which means teaching a lot of things twice, given the Venn Diagram shows large overlap. Your book, which I've been reading, takes the more integrated approach that I favor. Math teachers are in a tough position I think, as a lot of the mathy content that students find most attractive is being placed in another subject area. I have my opinions about all this, as a former high school math teacher turned applications programmer and teacher-trainer. https://medium.com/@kirbyurner/the-plight-of-high-school-math-teachers-c0fa… Finding a lot of computer science teachers in a hurry is the name of the game right now, and lots of educators are selling on ramp teacher training programs. That's becoming a big business. I expect many with a math teaching background are currently migrating to computer science, so in some sense my desire for better integration is being fulfilled. Some of this on ramp programs teach a language called Pyret, which we're told is the better way to go. Kirby On Tue, Jul 10, 2018 at 5:13 AM, Sergio Rojas <sergio_r(a)mail.com> wrote: > > > here's a blog post raising the alarm > > that Python (among others) is "completely incompatible with mathematics". > > > > > > https://blogs.ams.org/matheducation/2017/01/09/ > integrating-computer-science-in-math-the-potential-is- > great-but-so-are-the-risks/ > > > > I get lost reading the referred blog post. I was > under the impression that the ideas presented in the > post were already fully discussed back in the 90's, > when Mathematica was getting its way into the > classroom at US schools. That things like "x = x + x" > were already familiar to teachers. > > In fact, I was thinking of an open source alternative to Mathematica > when writing the book on Prealgebra via Python Programming > (https://www.researchgate.net/publication/325473565), with the > advantage that Python can be used for intensive computing task as > well as for symbolic (algebraic) computations (like mathematica) > via SymPy. > > I was under the idea that the Mathematica team has already shaped and > polished the road. I can see that I was wrong. It is still very, very > rough (much more than the first draft of my book). > > Sergio > > >

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excerpt from real world python class
by kirby urner 13 Jul '18

13 Jul '18

When I'm not doing exotic Martian Math summer school, sharing weird Portland math no one knows if not an American literature buff (1900s New England Transcendentalism), I'm teaching night school Intro to Python, in California, or nationwide, online. Tonight I was saying that whereas Python is named for Monty Python, I think Greek Mythology probably has a long half-life (it's not either/or anyway), so I'm into exploring Vaults of Parnassus etc., not a new idea among Pythonistas (to link to Greek myths). This is to explain some of the comments. >From tonight's summary meetup (last session, 10 of 10): ===== #!/usr/bin/env python3 # -*- coding: utf-8 -*- """ Created on Thu Jul 12 16:39:32 2018 @author: Kirby Urner """ class I: """ a goofy goofy I normally Pythonistas say self not me, but hey, it's just a placeholder. Free country. """ def __init__(me): me.stomach = [ ] # empty (subclasses use it) me.energy = 100 def __repr__(self): return "I live at {} on Memory Lane".format(id(self)) def __str__(me): return "Well hello, I'm a self" def selfie(me): "Click!" return me def __enter__(me): """ context manager I am """ return me.selfie() # same as return self def __exit__(me, *oops): if oops[0]: return False # woopsy, sorry about that return True def __del__(me): print("I now have one less refcount!") if __name__ == "__main__": with I() as me: print(me) print([me]) # me sticks around even after context ends other = I() print(other, "too") print([other]) del me del other ========== #!/usr/bin/env python3 # -*- coding: utf-8 -*- """ Created on Thu Jul 12 16:56:25 2018 @author: kurner """ from selfcentered import I class Foe(I): """ The mythical Python lived under Mt. Parnassus (Παρνασσός) and its breath (?) gave the Oracle of Delphi her powers of diagnosis and prognosis https://en.wikipedia.org/wiki/Pythia """ def __del__(self): # https://en.wikipedia.org/wiki/Athena_Parthenos print("Apollo thinks I'm dead, but I escaped to Nashville") global selfcentered import selfcentered selfcentered.Python = self # hide out in another module class Hero(I): """ Apollo is supposed to have slain the Python under Mt. Parnassus """ def __init__(self): super().__init__() print("A hero is born!") def eat(self, food : str): if not type(food) == str: raise ValueError self.stomach += [food] # yum! self.energy += 10 def slay(self): global Python if self.energy: del Python print("Foe slain") else: print("I'm too weary to fight. Feed me!") self.__spend_energy() def __spend_energy(self): if self.energy: self.energy = (self.energy - 10 if self.energy >= 10 else 0) if len(self.stomach): print("Digesting {}".format(self.stomach.pop(0))) def seek(self): print("seeking foe") self.__spend_energy() def __repr__(self): return "< Hero Energy:{} Stomach:{} >".\ format(self.energy, len(self.stomach)) if __name__ == "__main__": Python = Foe() # Foe Apollo = Hero() # Hero Apollo.eat("Manly Meal") print(Apollo.stomach) Hero.seek(Apollo) Apollo.seek() print(repr(Apollo)) Apollo.eat("Rats") Apollo.eat("Beer") Apollo.seek() Apollo.seek() Apollo.seek() Apollo.seek() print(repr(Apollo)) Apollo.slay() print(repr(Apollo)) Apollo._Hero__spend_energy() # remember name mangling? print(repr(Apollo)) print("Good bye Apollo") del Apollo ======= OUTPUT: runfile('/Users/mac/Documents/pyt-pr/Session10/heroic_story.py', wdir='/Users/mac/Documents/pyt-pr/Session10') A hero is born! ['Manly Meal'] seeking foe Digesting Manly Meal seeking foe < Hero Energy:90 Stomach:0 > seeking foe Digesting Rats seeking foe Digesting Beer seeking foe seeking foe < Hero Energy:70 Stomach:0 > Apollo thinks I'm dead, but I escaped to Nashville Foe slain < Hero Energy:60 Stomach:0 > < Hero Energy:50 Stomach:0 > Good bye Apollo I now have one less refcount! selfcentered.Python Out[26]: I live at 4892551320 on Memory Lane """LAB 3 UNTIL 10:10""" Out[20]: 'LAB 3 UNTIL 10:10' class Dog: def bark(self): print("Bark!") dog = Dog() dog.bark() Bark! Dog.bark(dog) Bark!

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Jupyter notebooks with exercises and solutions on Azure
by Santiago Basulto 11 Jul '18

11 Jul '18

Hello friends! I'm looking for a solution to share projects and homework with our students that would allow us to "hide" solutions for exercises. I'm aware of Exercise <http://jupyter-contrib-nbextensions.readthedocs.io/en/latest/nbextensions/e…> and Exercise2 <http://jupyter-contrib-nbextensions.readthedocs.io/en/latest/nbextensions/e…> from jupyter extensions (which both look great), but I can't seem to make them work on Azure notebooks. Any ideas? Thanks very much! PS: We're using Azure notebooks so we can get our students up and running without the need of installing Python + jupyter + libraries locally. But maybe there's another choice that would allow us to do this? -- Santiago Basulto.- Co-founder @ rmotr.com

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