Mailman 3 September 2000 - Edu-sig

Teaching Python at a Junior College Level
by Dean Nevins 18 Oct '00

18 Oct '00

I am a CS teacher who teaches a general service course (both majors and non-majors) and in it we have a programming component. Currently, we are teaching BASIC to the students but I _really_ don't like the bad habits that this language promotes and I like the ease of explaining programming concepts in Python to both CS majors and NON-CS majors. However, my problem is not the language but in trying to get a broader acceptance of Python as a language equivalent to BASIC in people's minds. We know that Python is better ('natch :-) but people responsible for transferring the credit to another school often will ask for BASIC specifically. Any ideas how to fix this problem? This problem is much more important than you might realize. If schools won't accept classes that have Python in them, then it doesn't matter how much better Python is than BASIC, the classes cannot be taught. Either that or you end up with boutique classes with nobody in them. Dean P.S. I'm in California if that matters.

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Anyone Explored Stackless python?
by Rick Richardson 05 Oct '00

05 Oct '00

has anyone worked with or checked out the stackless python as described here http://www.stackless.com/spcpaper.htm from the looks of things it would have the power to create incredible multi-threaded apps.. which is primarily my interest as I am creating a persistent object server that can glue multiple programs and languages together, acting more like a .dll than a DCOM or CORBA type server, python just seemed like the natural choice because of it's incredible extensibility. If any are interested, I would be more than happy to share it when I am finished, or even discuss design issues. Rick Richardson

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Code Examples using IDLE
by Kirby Urner 29 Sep '00

29 Sep '00

Greetings Fredrik -- No need to respond to this; I know you're super-busy. Just wanted to mention that we IDLE users like to tweak and reload modules quite a bit, including your Standard Library examples. You show how using __import__ directly gets around the fact you use hyphens in your module file names. However, your reload(hello) example doesn't show how to reload with hyphenated modules -- which for IDLE users is the easiest way to force re-evaluation of tweaked code. So for example when I first __import__("socket-example-1"), it executes and gives a server time. If I open this module in IDLE and change the server name, then I'd like to reload and have it execute a second time. I floundered around for awhile and then came up with a way to do it. My solution is to go: >>> v = __import__("socket-example-1") host is: www.python.org server time is Fri Sep 29 09:27:39 2000 local clock is 4 seconds off [change host in source code -- module open in window] >>> reload(v) host is: clock.sgi.com server time is Fri Sep 29 09:41:57 2000 local clock is 2 seconds off <module 'socket-example-1' from 'G:\PYTHON20\lundh\socket-example-1.py'> [change host in source code -- module open in window] >>> reload(v) host is: ntp-cup.external.hp.com server time is Fri Sep 29 09:43:08 2000 local clock is 2 seconds off <module 'socket-example-1' from 'G:\PYTHON20\lundh\socket-example-1.py'> I'm using some of the public access time servers listed on: http://www.eecis.udel.edu/~mills/ntp/clock1.htm Perhaps in some future draft of your excellent book, you could throw in a few words for the "IDLE community" (that makes it sound like we're lazy, which I guess in some sense is true). Kirby PS: I notice www.pythonlabs.com is not as friendly to testers: >>> reload(v) Traceback (innermost last): File "<pyshell#2>", line 1, in ? reload(v) File "G:\PYTHON20\lundh\socket-example-1.py", line 13, in ? s.connect((HOST, PORT)) File "<string>", line 1, in connect error: (10060, 'Operation timed out') Won't even give me the time of day :-( PPS: thanks again for sending source code examples. I'm anticipating hours of fun and games.

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Re: [Edu-sig] Tk from IDLE: How to 'Hello World'?
by Kirby Urner 29 Sep '00

29 Sep '00

>any thoughts? >- Jason > I've been getting advice to check out Boa from the newsgroup side as well. I've played with wxpython and the Pythonwin interface and didn't have any real problems. I deleted all that stuff when moving up to 2.0. I gather I'd need to go back to 1.5.2 to use these GUI tools, or at least they don't yet work on 2.0 beta. I've got both 1.5.2 and 2.0 in my Linux partition, so could test Boa over there if it's cross-platform (I'm still clumsy/slow in Linux world -- took quite awhile to figure out kpackage well enough to get 2.0/Tk out of the rpms, plus had to go find libreadline.so.3 or something first (still haven't wired Python 2.0 to an icon on my Helix Gnome interface)). Because I'm doing "math through programming" and not really focusing on how to build GUI apps, it wasn't high priority for me to explore Tk. My modules run directly in IDLE and don't depend on any GUI other than IDLE itself to work. But as I'm competing with TI graphing calculators to make Python a CLI of choice in the math classroom, I thought a nice little popup graphing display in Tk should be part of the package. Of course lots of folks have written such (tkgraph, what I was calling my module, is already out there by someone else), but I was taking this opportunity to learn enough Tk myself to pull one off. That's still my agenda. So that's the background. To date, IDLE has served all my needs very well, as my graphics have been out to the Povray rendering engine or to VRML viewers. I've long used some of the Microsoft IDEs for bread and butter programming, including Visual FoxPro's (which is far better than Access/VBA's when it comes to letting you write your own classes, including custom subclasses of the provided widgets -- VFP is way more powerful than Access overall, dunno why Microsoft seems to downplay it). Dragging and dropping widgets/controls from a palette to a form is very easy, then you right click and type in various properties -- the usual thing, what the Java IDEs aim for as well (same as VC++, Delphi, VB, in terms of generic look -- but somewhat different from SmallTalk environments). All of which is to say I know what a fancy IDE is like and see how much time they save when it comes to developing slick front ends that don't look out of place on a desktop (not that I'm strict about that for myself -- that "corporate look" just means "boring" a lot of the time). So if IDLE proves robust enough in 2.0 to accomodate my low intensity use of Tk, then I think I'll be satisfied with it for my little curriculum niche, which points students on to other resources for doing full-fledged GUI apps using Python, or to other languages/IDEs altogether, such as Java or Xbase. Kirby

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Re: Bug in 2.0b2: Tkinter (continued)
by Kirby Urner 29 Sep '00

29 Sep '00

Kirby Urner <urner(a)alumni.princeton.edu> wrote: > def drawborder(self): > top_l = (self.border,)*2 > top_r = (self.dim - self.border,self.border) > bot_l = (self.border,self.dim - self.border) > bot_r = (self.dim-self.border,)*2 > self.canvas.create_line([(top_l,top_r),(top_r,bot_r),(bot_r,bot_l),(bot_l,top_l)],fill='black') > OK, for one thing, the little border-maker (draws a picture frame around the sine wave) was completely out to lunch. The create_line function just wants to play connect the dots, whereas I was giving it these (vertex,vertex) tuples. So the program was barfing on drawborder. For another thing, as I posted below, someone tells me to do a root.mainloop(1) instead of root.mainloop(), and then the close box will return me to IDLE. Well, that works. With these changes to the code, my tkgraph.py (simple, home grown, not competing with anything at sourceforge) seems pretty stable. Python 2.0b2 (#6, Sep 26 2000, 14:59:21) [MSC 32 bit (Intel)] on win32 Type "copyright", "credits" or "license" for more information. IDLE 0.6 -- press F1 for help >>> import tkgraph >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> 2+2 4 >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() >>> tkgraph.testgraph() Look ma, no crash! I don't think it was the border glitch that was crashing me before. If you scan back in the postings, I was having trouble with 2.0b1 and Fredrik explained it was garbage collection and variably sized sequences that were to blame -- said it'd be fixed in 2.0b2. So of course I was looking forward to 2.0b2 and disappointed when I got similar kinds of crashes (and before adding the bogus border). So I'm still somewhat mystified as to what I can expect trying to use IDLE as a platform for Tk programming. Dave on edu-sig implies it's not stable. That was my experience, but now I've learned a new trick, squished a bug, and things are working a lot better. I'd appreciate any straight-talkin' jive turkey python guru coming along and spelling it all out for me. Dave seems to really know what he's talking about, so I gather IDLE has limitations as a Tk programming environment -- I just don't yet know when I've hit these limits, and when I'm still fighting my own code and/or ignorance of mainloop(1)-type features. Inquisitively, Kirby PS: Here's the more stable code (not that I expect anyone to run it): # simple graphing from Tkinter import * import math from operator import getitem class graph: def __init__(self,dim=410,border=5): self.dim = dim self.border = border self.scaled = [] self.sf = 0 self.functions = [] def addf(self,function): dom = map(getitem,function,[0]*len(function)) rng = map(getitem,function,[1]*len(function)) maxval = math.ceil(max(map(abs,dom+rng))) self.sf = max(self.sf,(self.dim-self.border*2)/(maxval*2)) self.functions.append(function) def drawgraph(self): self.root = Tk() self.canvas = Canvas(self.root,height=self.dim,width=self.dim, bg='white') self.canvas.pack() self.drawborder() self.plot() self.root.mainloop(1) def drawborder(self): top_l = (self.border,)*2 top_r = (self.dim - self.border,self.border) bot_l = (self.border,self.dim - self.border) bot_r = (self.dim-self.border,)*2 self.canvas.create_line([top_l,top_r,bot_r,bot_l,top_l],fill='black') def plot(self): for graph in self.functions: scaled = self.scaleinput(graph) self.canvas.create_line(scaled, fill='royalblue') def scaleinput(self,graph): dom = map(getitem,graph,[0]*len(graph)) rng = map(getitem,graph,[1]*len(graph)) return zip(map(self.pixel,dom),map(self.pixel,rng)) def pixel(self,val): return int(round(self.sf * val)) + self.border + (self.dim)/2 def testgraph(): dom = mkdomain(-math.pi,math.pi,0.1) # note step by 0.1 sine = zip(dom,[math.sin(x) for x in dom]) # sine function mygraph = graph() mygraph.addf(sine) mygraph.drawgraph() def mkdomain(low, high, interval): # create list of domain values, from low to high # stepping by interval output = [] # the output list i=0 while 1: # just keep looping... (assume parameters ok) output.append(low + i*interval) i=i+1 if output[-1]>=high: break # ...until high reached return output

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Tk from IDLE: How to 'Hello World'?
by Kirby Urner 28 Sep '00

28 Sep '00

Tk in Windows IDLE does not work the way tutorials suggest. For example, consider Fredrik Lundh's 'Hello World' app at http://www.pythonware.com/library/tkinter/introduction/hello-tkinter.htm Writing it interactively in IDLE, one would go: >>> from Tkinter import * >>> def test(): root = Tk() w = Label(root, text="Hello, world!") w.pack() root.mainloop() >>> test() Which gets you the Tk window saying Hello World, as expected. But then if you hit the close box, do you get back to a working IDLE prompt? I don't. I'm left in limbo, with a prompt I can't go back to. I haven't tested this in LINUX IDLE yet, nor in 1.5.2 -- so maybe this is a new phenomenon with the latest beta? Or is it some problem with my setup? Could another Windows user provide a reality check here? Anyway, Lundh's book and many other resources do not appear to be written with IDLE in mind. For example it states: To run the program, run the script as usual: $ python hello1.py But that's not 'usual' for an IDLE user. There's no $ prompt, and we're already in Python, and so wouldn't invoke it. As someone interested in using Python in schools, I think a GUI like IDLE is a potentially better learning environment than a command line in DOS or Xterm. I would like to see more bias in favor of using IDLE when doing work with Tk (IDLE being itself a Tk app, after all, and cross-platform). Kirby

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Python for the Visually Impaired
by JP S-C 27 Sep '00

27 Sep '00

Dear edu-sig and i18n-sig mailing lists, The subject of this message is somewhere in between education and internationalization, so I am writing you both. I run a project named Ocularis and am interested in collaborating with developers from both SIG's or the SIG's themselves. Ocularis in brief, is a distribution of the Linux Operating System that aims to allow the visually impaired to communicate, work, and express themselves through computers as well as to install and customize their system, independent of sighted assistance. The development of Ocularis is already underway and all software is created by volunteers and is released under the GNU Public License. More detailed information about Ocularis in included below. The ocularis-desktop package (currently in version 0.0.1) focuses on providing console-based applications that serve common functions. This package is written completely in Python, a language which I believe has a lot of potential for creating applications for the visually impaired. In addition, I think that Python is also an ideal language on many fronts, especially when it comes to programming, debugging, and maintaining code non-visually. Other than the ocularis-desktop package, there are also several developers who are working on other subprojects of Ocularis that aim to provide better access to X, including GTK-based applications. I would love to discuss or hear ideas from anyone about Python's many uses for and with the visually impaired. Thank you. --JP Schnapper-Casteras jpsc(a)users.sourceforge.net Details about Ocularis: The computing environment and suite of applications that are the goal of Ocularis will be free software (see "www.gnu.org" for a definition of free software) and will be based on Linux. The basic applications that Ocularis will possess are a word processor, calendar, calculator, basic accounting or finance application, file manager, Internet browser, and e-mail client. All of these programs will run smoothly on computers consisting of commonly available hardware costing less than $500 that can be bought at almost any local computer store. In comparison to current adaptive technology, this is both a drastic price drop and an increase in the availability of the required hardware. Ocularis was started in response to research on current adaptive technology, which culminated in the editorial "The Potential of Open Source for the Visually Impaired" (available at the Ocularis web site,"http://ocularis.sourceforge.net/"). For more information, please visit the Ocularis web site, "http://ocularis.sourceforge.net/", or contact me directly. __________________________________________________ Do You Yahoo!? Yahoo! Photos - 35mm Quality Prints, Now Get 15 Free! http://photos.yahoo.com/

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Re: [Edu-sig] More Pythonic Precalculus (Python 2.0)
by Kirby Urner 26 Sep '00

26 Sep '00

At 01:15 PM 09/25/2000 -0500, Dustin Mitchell wrote: >Kirby -- > >How about > >>>> f = lambda x : 2 * x * x - 10 * x + 2 Dustin, re your lambda-based approach, Jeff Cogswell just sent me the following: >>> f = "2 * x**2 - 10 * x + 2" >>> foo = eval("lambda x: %s" % f) >>> for i in range(10): foo(i) 2 -6 -10 -10 -6 2 14 30 50 74 ...which I think is brilliant, and likely faster than even David's solution since it evals only once. Here lambda makes more sense, and we get to start with a string. Kirby PS: there's likely a solution with compile and/or exec as well, but I haven't thought it through.

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Re: [Edu-sig] More Pythonic Precalculus (Python 2.0)
by Jeff Cogswell 26 Sep '00

26 Sep '00

Thanks for sharing my tip on the list, Kirby. I think I have things fixed and this email *should* make it to the list now. Jeff >From: Kirby Urner <pdx4d(a)teleport.com> >To: Edu-sig(a)python.org >Subject: Re: [Edu-sig] More Pythonic Precalculus (Python 2.0) >Date: Mon, 25 Sep 2000 19:18:52 -0700 > > >At 01:15 PM 09/25/2000 -0500, Dustin Mitchell wrote: > >Kirby -- > > > >How about > > > >>>> f = lambda x : 2 * x * x - 10 * x + 2 > >Dustin, re your lambda-based approach, Jeff Cogswell just sent >me the following: > > >>> f = "2 * x**2 - 10 * x + 2" > >>> foo = eval("lambda x: %s" % f) > >>> for i in range(10): foo(i) > >2 >-6 >-10 >-10 >-6 >2 >14 >30 >50 >74 > >...which I think is brilliant, and likely faster than even >David's solution since it evals only once. Here lambda makes >more sense, and we get to start with a string. > >Kirby > >PS: there's likely a solution with compile and/or exec as >well, but I haven't thought it through. > > > >_______________________________________________ >Edu-sig mailing list >Edu-sig(a)python.org >http://www.python.org/mailman/listinfo/edu-sig _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com.

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Inspired programming for everyone
by Jason Cunliffe 26 Sep '00

26 Sep '00

Hello For those of you interested in object oriented music programming, one of the best tools around must be Tim Thompson's brilliant KeyKit. http://nosuch.com/keykit/ The user interface system alone is well worth exploring, even if algothmic music is not your bag.. Building on top of this great platform, there is now an extraordinary graphical extension for it by a French artist-programmer called 'Stef'. He has developed GeoMaestro. Good Tutorials in French and English http://perso.infonie.fr/hepta/GM/eGM0.html It would be wonderful if such works of art and science were available for Python. ...shinging singing lights along the path to CP4E... much to learn from here and a symphony of fun enjoy - Jason ________________________________________________________________ Jason CUNLIFFE = NOMADICS.(Interactive Art and Technology).Design Director

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