Mailman 3 March 2010 - Edu-sig

xturtle online via processing.js !?
by Jurgis Pralgauskis Sept. 27, 2012

Sept. 27, 2012

Hi, I am struggling around with interactive online py tutorials with https://launchpad.net/projects/intro-to-code (ith might become securely sandboxed soon, as pypy made it possible http://blog.sandbox.lt/en/WSGI%20and%20PyPy%20sandbox :) but one more thing is I'd like to let access xturtle functionality online - one possible way could be triggering tkinter to save its canvas to ps, and then convert them with imagemagic and show via web (animated gif or static) - but if pyjamas can render … [View More]

4 6

Confused how teach geometry and importance of teaching geometry in 21st century.
by chris＠seberino.org April 10, 2010

April 10, 2010

I'm teaching high school math to homeschoolers and I'm looking for how to make geometry year meaningful. I'm having a "crisis of confidence" because from my viewpoint, algebra was 10x more useful for future math and science work. The only thing I can remember that was useful from geometry was a few volume and area formulas. That can justify maybe a month but not a whole YEAR of geometry!?!? cs P.S. Yes yes I know that geometry is meant to teach logical reasoning. Maybe one can get that … [View More]

7 8

Dreaming in Code by Scott Rosenberg (2007)
by John Graves March 28, 2010

March 28, 2010

This book is about the open source, python-based Chandler project ( http://chandlerproject.org/ last mentioned on Edu-sig in 2006) and, more broadly, about the art of creating software. Here is the website for the book: http://www.dreamingincode.com/ And a Salon interview with the author: http://www.salon.com/books/int/2007/02/03/leonard/ Surprisingly, this book has not been mentioned before on Edu-sig if a Google search of the archives is to be believed. Here are excerpts [and comments on … [View More]the excerpts] which suggest why it might be useful to Python-using Educators: pg 41 Torvalds, who is known as Benevolent Dictator for Life of the Linux operating system, consistently exudes a calm optimism about the long-term prospects for the movement he symbolizes. "In science," as he explained in a 2004 interview in Business Week, "the whole system builds on people looking at other people's results and building on top of them. In witchcraft, somebody had a small secret and guarded it--but never allowed others to really understand it and build on it. Traditional software is like witchcraft. In history, witchcraft just died out. The same will happen in software. When problems get serious enough, you can't have one person or one company guarding their secrets. You have to have everybody share in knowledge." [Are the principles of open source and the reading of well written code parts of your curriculum?] pg 43 In the 1962 essay that laid out his plan of research into the augmentation of human intelligence, Engelbart explained why computer programmers were the most promising initial target group. ... [He] noted that "successful achievements can be utilized within the augmentation-research program itself, to improve the effectiveness of the computer programming activity involved in studying and developing augmentation systems. The capability of designing, implementing, and modifying computer programs will be very important to the rate of research progress." In other words, if NLS [oNLine System] could help his programmers program better, they'd be able to improve NLS faster. You'd have a positive feedback loop. You'd be, in the term Engelbart favored, bootstrapping. To Engelbart, bootstrapping meant "an improving of the improvement process." pg 98 "If it takes the typical programmer more than two minutes and twenty-seven seconds to find something," Constantine wrote, "they will conclude it does not exist and therefore will reinvent it." [How do you teach code reuse and enhancement?] pg 127 There is no reliable relationship between the volume of code produced and the state of completion of a program, its quality, or its ultimate value to a user. ... The week that he was asked to fill out the new management form for the first time, Atkinson had just completed rewriting a portion of the Quickdraw code, making it more efficient and faster. The new version was 2000 lines of code shorter than the old one. What to report? He wrote in the number -2000. [What do you teach students to produce -- code or value-to-the-user?] pg 149 In 1990, at the PC Forum gathering of computer industry luminaries, Kapor first delivered the text of his "Software Design Manifesto." No one is speaking for the poor user. ... Perhaps the most important conceptual move to be taken is to recognize the critical role of design, as a counterpart to programming, in the creation of computer artifacts. ... Reaching back to ancient Rome, Kapor proposed applying to software the architecture theorist Vitruvius's principles of good design: firmness--sound structure, no bugs; commodity--"A program should be suitable for the purposes for which it was intended"; delight--"The experience of using the program should be a pleasurable one." [What design principles do you teach? How do they compare?] pg 245 [In "Methods" chapter, discussion of CMM:] One Humphrey presentation offered these bluntly persuasive bullet points: - We all work for organizations. - These organizations require plans. - Unless you are independently wealthy, you must work to a schedule. - If you don't make your own schedules, somebody else will. - Then that person will control your work. pg 252 The meeting found a more virile name for the movement--Agile Software Development--and produced a manifesto that reads in its entirety: We are uncovering better ways of developing software by doing it and helping others do it. Through this work we have come to value: - Individuals and interactions over processes and tools - Working software over comprehensive documentation - Customer collaboration over contract negotiation - Responding to change over following a plan [Do you expose students to these ideas?] pg 306 Knuth's faith is distilled in the haiku-like poem by the Danish poet/scientist/designer Piet Hein that adorns the entryway to his home: The road to wisdom?--Well, it's plain and simple to express: Err and err and err again but less and less and less. Literate programming is intended as an antidote to the excruciating fact that, as Joel Spolsky puts it, "it's harder to read code than to write it. Instead of imaging that our main task is to instruct a computer what to do, let us concentrate rather on explaining to human beings what we want a computer to do. [By implication, if you do not teach literate programming, you teach "illiterate" programming! ;-) ] pg 268 [Rosenberg's Law] Software is easy to make, except when you want it to do something new. [corollary] The only software that's worth making is software that does something new. [see also discussion at http://www.wordyard.com/2007/01/15/rosenbergs-law/ ] pg 314 After spending some time studying Chandler's code base, Eby posted to his blog a lengthy entry titled "Python Is Not Java." ... So, the sad thing is that these poor folks worked much, much harder than they needed to, in order to produce much more code than they needed to write, that then performs much more slowly than the equivalent idiomatic Python would. ... Pretend that Python is a magic wand that will miraculously do whatever you want without you having to lift a finger. Ask, "how does Python already solve my problem?" and "What Python language feature most resembles my problem?" You will be absolutely astonished at how often it happens that [the] thing you need is already there in some form. [ http://dirtsimple.org/2004/12/python-is-not-java.html ] ---- I found the book very informative and inspiring--especially in light of another open source, Python-based project, Open Allure, a voice-and-vision enabled educational software, which is part of my PhD study of open source software development. If you are interested in following this project, check out the short videos at http://bit.ly/openallure join the discussion list at http://bit.ly/openalluregg or get the source code at http://openallureds.org John Graves Auckland NEW ZEALAND [View Less]

4 4

about iterators, range, and summing consecutive integers
by kirby urner March 27, 2010

March 27, 2010

Here are some looks at summing consecutive integers, ways to sum 1 + 2 + ... + n in Python: We start with the closed form, which doesn't actually need to iterate through intermediate terms, works directly with n, the last term in the sequence: >>> def trinumbs(n): return n * (n + 1) // 2 These next two make use of all the intermediate values: >>> def trinumbs2(n): return sum(range(1,n+1)) >>> def trinumbs3(n): i = 1 thesum = 0 while i <= n: thesum = … [View More]thesum + i i += 1 return thesum <Lore> Although all of these give the same answers, between the last two, the very last one is the most "classic" in terms of what an old time imperative programmer would expect. Having a range() function built right into the language is more APL-like. Most "classic" imperative languages such as FORTRAN and PL/1 required the programmer to do all the incrementing "by hand" (explicitly). You will find more about the range() function below. Notice the two ways of incrementing and rebinding. When writing thesum = thesum + i, the name 'thesum' is being rebound to the result of thesum plus whatever value i names. The equal sign (=) is not used to assert equality but as an "assignment operator". Objects have names and the assignment operator is what binds a name to an object. i += 1 is a shorter way of saying i = i + 1 and is borrowed from C / C++, is a much used convention. </Lore> Python has very few control statements. Another way to write the above would be: >>> def trinumbs4(n): i = 1 thesum = 0 for i in range(1, n+1): thesum = thesum + i return thesum The keywords 'while' and 'for' are the two main looping constructs. trinumbs2 is making use of another built-in that directly consumes the output of range( ), and that is the sum( ) function. Since range( ) is zero-indexed, and since our tacit understanding is we're working with "natural" or "counting" numbers starting with 1, both uses of range (in trinumbs2 and trinumbs4) bump up the starting and ending parameters. If you feed only one argument to range, this is mapped to its ending parameter with the start parameter defaulting to 0. range ( 10 ) is equivalent to range (start = 0, stop = 10), except range doesn't take keyword arguments, so you can't actually get away the the 2nd expression. Examples: Only one parameter, so an ending parameter: >>> list ( range( 10 )) [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] Two parameters, so a starting and ending parameter: >>> list ( range(1, 11 )) [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] Three parameters, so a starting, ending and "increment by" or "step" parameter: >>> range(2,31,2) range(2, 31, 2) >>> list ( range(2,31,2) ) [2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30] Yes, you may increment negatively, but then remember not to make your starting value less than your stopping value: >>> list ( range(1, 10, -1) ) [] >>> list ( range(10, 0, -1) ) [10, 9, 8, 7, 6, 5, 4, 3, 2, 1] range(5) returns a "range object" (of type range) which may in turn be interacted with in various ways: >>> d = range(5) >>> d range(0, 5) >>> type(d) <class 'range'> >>> list(d) [0, 1, 2, 3, 4] >>> tuple(d) (0, 1, 2, 3, 4) >>> sum(d) 10 How else might we address a Python range object? With slicing notation: >>> d[1] 1 >>> d[4] 4 Although it's an iterable (you may iterate over it, using 'for'), d is not an iterator, meaning it's not supportive of 'next' (as no __next__ rib internally). The built-in iter function will trigger an object's internal __iter__ method, if there is one, and return an iterator prepared to be eaten by next(). >>> next(d) Traceback (most recent call last): File "<pyshell#44>", line 1, in <module> next(d) TypeError: range object is not an iterator >>> k = iter(d) >>> next(k) 0 >>> next(k) 1 >>> next(k) 2 >>> d range(0, 5) >>> j = iter(d) >>> next(j) 0 >>> next(k) 3 Notice that k and j above are two separate iterators and they go through to exhaustion independently of one another. Once an iterator has been exhausted, it will no longer return contents, including in response to the print function. >>> theiterator = iter(d) >>> next(theiterator) 0 >>> next(theiterator) 1 >>> print(theiterator) <range_iterator object at 0x0114AA28> >>> print(list(theiterator)) [2, 3, 4] >>> next(theiterator) Traceback (most recent call last): File "<pyshell#68>", line 1, in <module> next(theiterator) StopIteration In the above example, d (which is our range object) is the source of a fresh iterator, theiterator. After nexting through two terms, the print function is used. The first use simply returns the type of the object, not its contents. However, by feeding theiterator to the list function, we cause it to squirt out the rest of its contents, meaning it is now exhausted. When theiterator is then fed to the next method, it raises an exception, a StopIteration. >>> def test(): try: next(theiterator) except StopIteration: print("I'm exhausted") >>> test() I'm exhausted Note that the range object is happy to return a "reversed" iterator, so instead of stepping by -1, you might do something like: >>> theiterator = reversed(range(10)) >>> next(theiterator) 9 >>> next(theiterator) 8 >>> for item in theiterator: print (item, end=" ") 7 6 5 4 3 2 1 0 Here's an author unhappy with Python's iterators. His commentators debate him. You may learn more about a language by reading the arguments people have about it. What's frustrating. What's considered "a wart". http://sandersn.com/blog//index.php/2009/06/29/python_s_iterators_are_a_bad… You might imagine how iterators could contribute to a programmer's confusion, when trying to debug code. They're not like collections of static data, are more like "mortal coils" or one-time-through sequences. An iterator passed to a function and partially advanced, with have been modified "off stage". >>> theiterator = reversed(range(10)) >>> next(theiterator) 9 This function returns nothing, but has the effect of advancing the passed in iterator. The object being passed in is bound to the name theinput for local processing, which name goes out of scope when the function is finished. However, the object still persists "on the outside" and has been affected by what went on in this function. >>> def squeeze_me( theinput, howmany): for i in range( howmany ): next( theinput ) >>> squeeze_me ( theiterator, 3 ) >>> next(theiterator) 5 <Arcane> Here's an instructive example of changes to Python's behavior resulting in new wrinkles: http://lists.fedoraproject.org/pipermail/devel/2009-September/037966.html The __length_hint__ attribute (mentioned in the above report) is one you might use to get a sense of how close your iterator might be to exhaustion. When converting an iterator to a list, this attribute is apparently consulted, which is what was causing problems in a user-defined class (__get_attr__ had been redefined). This problem has apparently been resolved in Python 3.x as I'm getting the expected behavior. </Arcane> More dialog with "the snake": >>> thelist = ['a',1,2,['another','list']] >>> next(thelist) Traceback (most recent call last): File "<pyshell#55>", line 1, in <module> next(thelist) TypeError: list object is not an iterator >>> '__iter__' in dir(thelist) True >>> theiterator = iter(thelist) >>> next(theiterator) 'a' >>> next(theiterator) 1 >>> next(theiterator) 2 >>> next(theiterator) ['another', 'list'] >>> next(theiterator) Traceback (most recent call last): File "<pyshell#62>", line 1, in <module> next(theiterator) StopIteration >>> For further reading: http://worldgame.blogspot.com/2009/11/kicking-can-down-road.html Kirby [View Less]

1 1

Did you feel learning to program with turtle graphics was useful?
by Daniel Ajoy March 27, 2010

March 27, 2010

stackoverflow discussion: http://stackoverflow.com/questions/346061/did-you-feel-learning-to-program-… Daniel

1 0

Re: [Edu-sig] Confused how teach geometry and importance of teaching geometry in 21st century.
by Litvin March 26, 2010

March 26, 2010

At 10:40 PM 3/25/2010, you wrote: >I'm teaching high school math to homeschoolers and I'm looking for how to make >geometry year meaningful. > >I'm having a "crisis of confidence" because from my viewpoint, algebra was 10x >more useful for future math and science work. The fact that geometry is considered a place to teach formal reasoning (and not much more) is peculiar to the math standards in this country. Properties of congruent triangles and other trivial stuff can be … [View More]

1 0

Fwd: course outline (pythonic math)
by kirby urner March 26, 2010

March 26, 2010

Here's something I originally posted to another list, but one that is white-space insensitive. Hardly a venue for sharing anything Pythonic. Anyway, it's relevant here too. This is more of a sketch than something I've poured over for hours, just trying to give the gist of a possible Discrete Math course, one among hundreds or thousands or... not trying to write "the national standard" (blech). Kirby ==== DIGITAL MATH: Cardinality versus Ordinality Naming things Two different … [View More]versus two the same Of zip codes and phone numbers Sorting things Equality, greater than, less than Hello World! A Biotum Class (Python) A Snake Class (Python) Numbers and Bases Positional Notation Lore: Algorithms liberate Europe (Liber Abacci) Lore: from ASCII to Unicode Decimal versus Hexadecimal Volume Bases: Tetrahedron versus Cube Functions and Relations (Part 1) Lore: the rise and fall of New Math Mappings Python's dictionary structure Caesar Codes Lore: from secret key to public key crypto Inverse Functions Injection, Surjection, Bijection What's a Relation? On Growth and Form Functions for Gnomon Growth Triangular Numbers Lore and Proof: Gauss summing 1..100 Square Numbers Proof: Sum of consecutive squares Tetrahedral Numbers Cubic Numbers Lore: Fibonaccis and Phi Generating Fibonaccis Generating Polyhedral Numbers Generating Pascal's Triangle Triangular and Tetrahedral Numbers Prime and Composite Numbers Euclid's Method for GCD Primes versus Composites Strangers Totatives and Totients Functions and Relations (Part 2) Permutations Polyhedral Rotations (dice in Casino Math) Composition of Functions (a kind of multiplying) Abstract Algebra I Multiplication: What is it Python and "Modulo Numbers" Vegetable Group Soup Cayley Tables Group Properties (CAIN and Abelian) Addition: What is it Rings and Fields Preview of Future Topics Supermarket Math SQL web frameworks Neolithic Math artifacts and encoded geography constellations Casino Math random number generators (Python) Deck and Card classes (Python) Martian Math Sphere packing and the Octet Truss Tetrahedral Accounting Pentagon Math Lore: geodesic spheres and domes, radomes Phi in Fuller's concentric hierarchy Notes for Teachers: Cardinality versus Ordinality -- Before we order or sort, we need to recognize which things or objects are of which type. This course uses a type based mathematical logic known as the Python computer language, so awareness of types will be front and center from the get go. Exercises will include querying objects as to their types. Z-axis (depth dimension): if you've going through this in a spiral with plans to go deeper each time, then at some point your students may want to define their own classes and implement meanings for __lt__ __gt__ __eq__, Python's "ribs" (special names) for < , > and == respectively. However, this course outline does not make too many assumptions about which turn of the spiral one is in. Students will vary, as will teachers. Numbers and Bases -- This should feel like fairly easy review. I recommend playing Tom Lehrer's 'New Math' from 'That Was the Year that Was' and making sure students get that it's mathematically correct. This is looking ahead to later lore, where we talk about the rise and fall of New Math. About Lore: this curriculum is premised on the notion that storytelling is integral to passing on a culture, and that too much time on a technical axis, to the exclusion of narrative context, is either counter-productive or is an intentionally applied filter aimed at testing student tolerance for "in the dark" learning. Functions and Relations (Part 1) -- A lot of this is standard Algebra 1. New Math helped writers formalize their notion of function as distinct from a relation, using set theoretic constructs. This may not be the right place for a Python dictionary on a first pass. I was getting into Caesar Codes again recently, relating them to permutations and polyhedral rotations, and am freshly persuaded this is one of the better routes to elementary group theory, just ahead. http://mail.python.org/pipermail/edu-sig/2010-March/009867.html http://mail.python.org/pipermail/edu-sig/2010-March/009870.html On Growth and Form -- Here's a way to connect the graphical and lexical without getting into XYZ coordinates or vectors right off. Gnomon studies and sphere packing keep the number sequences connected to the visualizations. Influences and valuable resources here would include 'The Book of Numbers' by Conway and Guy, 'Gnomon' by Midhat Gazale, and certain passages from 'Synergetics' by R.B. Fuller, with bolstering writing from H.S.M. Coxeter. Lore: getting a sense of Coxeter's outrage on finding nature's geometry had been patented by Fuller prefigures a generic distrust of the private ownership paradigm when applied to common natural heritage. In some classes, this might lead to a discussion of the free and open source software movement. I didn't include that in this particular segment though, as we're running low on time. Look in Pentagon Math under Future Topics. Abstract Algebra I -- Because Python makes our exercises much more concrete and hands on, especially with scaffolding (pre-written / canned libraries or modules), it's new feasible to get more abstract. 'Concrete Mathematics' is an influence ('con' from continuous, 'crete' from discrete). With this kind of groundwork in place, it becomes easier to review topics such as dividing fractions, as we may now talk about division as "syntactic sugar" for "multiplying by the multiplicative inverse". Reviewing such basic concepts as the four operations with Q (Rational Numbers) would not be out of place in this segment. Preview of Future Topics -- If this course or talk was used as a teaser or sampler, then here would be another chance to look ahead. I don't have anything on Pentagon Math at the Wikieducator site (Heuristics for Teachers). That's because you can easily fold it in with Neolithic and/or Martian Math. I split it out here because I wanted to dig into some of the lore in the Siobhan Roberts bio of Donald Coxeter. Remember: we think lore is very important, as are exercises and time alone with the Python interpreter (not all programming is pair programming in these initial stages, nor even later on -- depends on the project). For further reading: http://www.4dsolutions.net/presentations/p4t_notes.pdf Kirby [View Less]

1 0

Python projects for CS1
by Bill Punch March 24, 2010

March 24, 2010

Given all the discussion about exercises, we though we'd throw in some of the work we've done. MSU has taught its CS1 course in Python since the Fall of 2007. Each semester we have the students complete 11 programming projects (as homework). The homeworks start out easy and work their way up. Each project focuses on a particular topic i.e., strings, working with files, dictionaries etc. We've collected those projects on a webpage. Each project has some supporting material and a solution. … [View More]

5 7

"Computer Science For Kids" Book Announcement
by Andre Lessa March 24, 2010

March 24, 2010

Hey Python Community, I just self published this brand new book and I'm making its PDF available for (free) download on my web site. My goal is to explain some very basic fundamentals of computer science to kids who are starting to learn about computers at school and/or at home. For the tiny hints of programming, I referenced Python. If you (or a kid you know) ends up having access to this book, please send your feedback (suggestions/corrections) directly to me so I can start thinking about … [View More]

4 3

Re: [Edu-sig] Python projects for CS1
by Phil Wagner March 23, 2010

March 23, 2010

This is so perfect for what I am trying to do in my math class. I also appreciate the format. It is very clear and should be perfect for students. Thank you so much for sharing! Phil -- http://www.google.com/profiles/philhwagner http://staff.hthcv.hightechhigh.org/~pwagner/ (My Digital Portfolio)

1 0