Mailman 3 January 2005 - Edu-sig

Re: [Tutor] what? (late nite entertainment) (*)
by Gregor Lingl 25 Mar '05

25 Mar '05

Now: early morning corrections ... Alfred Milgrom wrote: > Hi Gregor: > > Hard to work out what is what :) as there seems to be a typo in one > line of your code: > > if x[z]: x[z*z:n:z]=y[z*z:n:z] > > (At least it doesn't work on my machine with Python 2.2) > Yeah, I had the idea when playing around with some new features of Python 2.3, as I do sometimes late at night - before shutting down my computer. This one I found at: http://www.python.org/doc/2.3.3/whatsnew/section-slices.html and I looked for an example for use of "assignment with extended slices" ... > Also the subroutine breaks for n = 1 or less. > Maybe you need a line at the start to say > if n <2 : return [0] > what() was intended to generate all primes less than n. (In fact it's an implementation of the sieve of Eratosthenes). The bugs came not only from not beeing interested in primes less than 2 ;-) but also from beeing a little tired already. Sorry. I think the following version repairs that - and hopefully uses less obfuscating variable names (which in fact originally was part of the "riddle"): def primes(n): sieve, zeros = range(n), [0]*n sieve[:2]= 0,0 i = 1 while i*i < n: if sieve[i]: sieve[i*i:n:i]=zeros[i*i:n:i] i += 1 return [p for p in sieve if p] Regards, Gregor >

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satacad python pdx
by Kirby Urner 08 Feb '05

08 Feb '05

Hi folks -- this is some more legwork around the Python class I'm about to start, in the capacity of instructor (I of course do Python classes as a student as well -- like at Pycon or OSCON or like that). I'm being somewhat thorough in showing what this looks like from the inside, in hopes of inspiring others to consider similar strategies, e.g. teaching Python with some other language, while focusing on some knowledge domain (math in this case). I'm not saying all these strategies should be adopted across the board, just that you might get some good ideas following my progress. For starters, find out if your community offers a similar infrastructure for offering academic enrichment outside of normal schooling. It'll likely be university-based or university-connected. Consistent with the goals of CP4E, we need to get Python in the hands of many more students than just the CS majors. Posting to the J Forum appended. Kirby -----Original Message----- From: Kirby Urner [mailto:kirby@4DSOLUTIONS.NET] Sent: Monday, January 03, 2005 8:25 PM To: JFORUM(a)PEACH.EASE.LSOFT.COM Subject: [Jforum] Urner rejoins, intro Greetings J-ists -- I was subscribed some time ago, as maybe the archives will disclose, and now I'm back, in part because I'm scheduled to teach a computer course starting this Saturday, and I intend to focus on both J and Python. Here're some details: --- Explore topics in mathematics by writing and modifying programs in a contemporary computer language. A goal of this class is to help you gain proficiency as a programmer, while delving into number theory, group theory, chaos and fractals, cryptography, 3D graphics and more. A primary tool will be Python, an object oriented, uncluttered, general purpose language. For contrast and mind expansion, the J language will also be introduced. Instructor: Kirby Urner, with a BA in philosophy from Princeton University , is a computer programmer and educator. He has developed computer literacy products for McGraw-Hill and is a former high school mathematics teacher. --- I'm not a black belt J programmer, but do have some appreciation for it, APL being my first love as a language (Princeton had APL workstations scattered around campus in the 1970s, wired to the IBM 370 mainframe). Here's a web page I published as a result of my explorations in J awhile back: http://www.4dsolutions.net/ocn/Jlang.html I'm somewhat rusty at this point, and I think reading posts on the J list will be a good way to help me limber up a bit. I'll also paw through the archives a bit to find out what's been going on. Kirby NOTE: I'm cross-posting this to edu-sig (@ python.org), where I'll be doing some archiving about this course as well. As a rule of thumb, I will *not* cross-post between these two lists (I know how annoying that can be). -------------------------------------------------------------------------- For information about the J Forum see http://www.jsoftware.com/j_forum.htm

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re: Naming in Python
by Arthur 03 Feb '05

03 Feb '05

I wrote - >Any opinions as to whether the following is an insight, or the kind of >pseudo-incite I tend to realize I have had when I sober up in the morning? >That the "readability" of Python is built-in to the structure of the >language in a largely non-obvious way, and has little to do with white >space significance, surface level syntax, etc. >Python is a "naming" language. The interpreter is working with assigned >names of objects more directly and more significantly than in other >languages (of which I am aware). As a programmer, one is conversing with >the interpreter by way of these names, as names and objects are closely >bound. And it therefore seems intuitively sensible to make names >significant, because in fact they are significant at a low and technical >level. >As opposed to C, for example. Which sort of laughs of you for going to the >trouble for adding extra keystrokes to placeholders. >Or something along these lines. I'll sink to commenting on my own post. Not the first time. Sobering up - I still think the observation has real substance. Though it is only an insight to the extent that it is non-obvious. I guess that depends on who you are and where you are coming from. It took me a while to get here. Art

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IDLE refusing to run
by Greg Baker 31 Jan '05

31 Jan '05

We have had complaints from a few students running Python under Windows that they can't get things running. All seem to take the form: 1. At some point, Python/IDLE under Windows crashed. 2. IDLE won't run at all after that. 3. The regular interpreter will run (python.exe). 4. Uninstalling/reinstalling doesn't help. Does anybody have any idea what to do about this? (Or who to ask?) I haven't been able to reproduce it to test, but it has happened to several students independantly. -- Greg Baker, Lecturer School of Computing Science Simon Fraser University Burnaby, BC, V5A 1S6 E-mail: ggbaker(a)cs.sfu.ca

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RE: [Edu-sig] re: Naming in Python
by Arthur 30 Jan '05

30 Jan '05

> -----Original Message----- > From: Kirby Urner [mailto:urnerk@qwest.net] > > > Maybe a break-out session on Wittgenstein at PyCon ;) > > > > Art > > Well, at least you and I should talk, maybe over a beer. Beer. I'll have to try to remember my ID ;) Look forward to it. Art

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RE: [Edu-sig] re: Naming in Python
by Arthur 30 Jan '05

30 Jan '05

> -----Original Message----- > From: Kirby Urner [mailto:urnerk@qwest.net] > Sent: Saturday, January 29, 2005 11:18 AM > To: 'Arthur'; edu-sig(a)python.org > Subject: RE: [Edu-sig] re: Naming in Python > > > Hi Art -- > > I've been thinking about your observation, but haven't come up with a > really > coherent way to extend your thinking, in such a way that a prove I know > what > you mean. Per Wittgenstein (a philosopher I like, and his philo the focus > another eGroup I post in), if you go 1, 12, 42 and I go 92, 162, that > sort > of proves I have an idea about the rule you're using (or maybe not?). Wittgenstein, huh? In an introduction to one of Wittgenstein's books, Bertrand Russell notes the influence of projective geometry on Wittgenstein - saying something to the effect that Wittgenstein applied projective geometry concepts to linguistics. Getting past Russell's introduction and into Wittgenstein writing itself, I pretty much get nowhere. It is a case where I would need to be taught - get some guidance from someone who has broken through. Or perhaps I don't have the background in philosophical ideas and history, to understand the context of Wittgenstein's thought. Maybe a break-out session on Wittgenstein at PyCon ;) Art

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Re: [Edu-sig] Naming in Python
by Christian Mascher 29 Jan '05

29 Jan '05

Arthur wrote: > Python is a "naming" language. The interpreter is working with assigned > names of objects more directly and more significantly than in other > languages (of which I am aware). I can imagine of one, see below. > As a programmer, one is conversing with the > interpreter by way of these names, as names and objects are closely bound. You mention two special features: 1. Every "variable" is _always_ just a pointer/reference to an individual object. So most of the time you don't even have to think of this level of indirection. And you can assign just about anything to a name. 2. "Live objects" can be examined on the spot in the interpreter. You don't have this in compiled languages. Interestingly instructors in Java seem to like this feature , too. When the language doesn't provide for it, you need an intermediate (interpreter-like) program to simulate the experience. Take the BlueJ-environment, where you can manipulate objects in a comparable way (or even through uml-editors and such). Still, this is not only a feature of the language as such, but also of the "environment" or the tools you use together with the language. It's not being interpreted alone, it's the IDLE-shell (rather than the simple command-line), the dir() function, the always accessible module code, documentation close to the source and the flexibility in assigning names whenever you want to. I have found one language which is very similar to Python in respect to the two mentioned characteristics and that is Smalltalk. The variable-concept (everything is an object, every variable a pointer), and the "live environment"-approach to programming are both going back at least as far as Smalltalk-80. (Didn't Guido mention Smalltalk as one of his influences somewhere?) I think both languages "feel" very similar in this way. You can interact with live objects, change them in small steps, examine them (e.g. dir() in Python, inspect in Smalltalk). Programming is fun in both cases. Who needs .exe-files really? Christian

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Re: [Edu-sig] re: Naming in Python
by ajsiegel＠optonline.net 29 Jan '05

29 Jan '05

----- Original Message ----- From: ajsiegel(a)optonline.net Date: Saturday, January 29, 2005 2:55 pm Subject: Re: [Edu-sig] re: Naming in Python > > as long as the things all have a method named "quack", and not > caring what each thing is and what quack does in context for > any particular thing. > > ...this being one way in which what I name something is to the essence > of my code and why I am inclined to pay attention to names. And while > I'm paying attention to names in this way anyway, I am inclined to > be > sensible in choosing them. And far be it from me to steer clear of a controversy: The convention in VB is, I believe, to name according to type: dblNumber, for example. which would be some evidence that type and naming are intuitatively related, and perhaps gives us some additional clue as to why the issue of typing raises such hackles, and carries such a sense of tinkering with Python at its distinctive core. Art

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Re: [Edu-sig] re: Naming in Python
by ajsiegel＠optonline.net 29 Jan '05

29 Jan '05

----- Original Message ----- From: Rodrigo Dias Arruda Senra <rsenra(a)acm.org> Date: Saturday, January 29, 2005 2:11 pm Subject: Re: [Edu-sig] re: Naming in Python > Perhaps this is a duck typing style of defining what > an object *is*. Interesting that the discussion here led to duck typing, because I was about to use the term myself to explain myself re: naming more generally. Python is happy to oblige us with for thing in things: thing.quack() as long as the things all have a method named "quack", and not caring what each thing is and what quack does in context for any particular thing. ...this being one way in which what I name something is to the essence of my code and why I am inclined to pay attention to names. And while I'm paying attention to names in this way anyway, I am inclined to be sensible in choosing them. Not pinned down, but something along these lines is my point. Happens, BTW, that I was accused on python list of not understanding Python because I don't understand duck typing. My response was something to the effect that it is easier for me to understand how Python works, and if that is called duck typing, I'm OK with that. Trying to understand what duck typing is, as a means to understanding how Python works, is - at least in terms of how my mind works - the wrong way around. Art .

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Naming in Python
by Arthur 28 Jan '05

28 Jan '05

Any opinions as to whether the following is an insight, or the kind of pseudo-incite I tend to realize I have had when I sober up in the morning? That the "readability" of Python is built-in to the structure of the language in a largely non-obvious way, and has little to do with white space significance, surface level syntax, etc. Python is a "naming" language. The interpreter is working with assigned names of objects more directly and more significantly than in other languages (of which I am aware). As a programmer, one is conversing with the interpreter by way of these names, as names and objects are closely bound. And it therefore seems intuitively sensible to make names significant, because in fact they are significant at a low and technical level. As opposed to C, for example. Which sort of laughs of you for going to the trouble for adding extra keystrokes to placeholders. Or something along these lines. Art

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