🌐 Mailman 3 January 2009 - Python-list - python.org

f.seek() unwanted output
by thomasvangurp＠gmail.com Jan. 5, 2009

Jan. 5, 2009

I'm having trouble with a script that is printing the output of f.seek () whereas in the documentation it is quoted not to have any output: ---- file.seek(offset[, whence])¶ Set the file’s current position, like stdio‘s fseek. The whence argument is optional and defaults to os.SEEK_SET or 0 (absolute file positioning); other values are os.SEEK_CUR or 1 (seek relative to the current position) and os.SEEK_END or 2 (seek relative to the file’s end). There is no return value. -------------- I have a file in memory. when i try f.seek(0) #or any other value in f.tell() it gives me 0 as output: the following script illustrates my 'problem' >>> for a in range(10): f.seek(a) 0 1 2 3 4 5 6 7 8 9 >>> I don't want python to produce output when setting the file pointer. Any help woul be appreciated. Kind regards, Thomas

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Tkinter - problem closing window
by Djames Suhanko Jan. 5, 2009

Jan. 5, 2009

Hello! I'm sorry my terrible english (my native language is portuguese). I has a litle program that open another window. When I close de root window in quit button, I need clicking 2 times to close. is where the problem? The source: 1 #!/usr/bin/env python 2 from Tkinter import * 3 import sys 4 import random 5 class App: 6 def __init__(self, master): 7 frame = Frame(master) 8 frame.pack() 9 rotulo = Label(frame, text="Clique em 'Gerar' e boa sorte!",borderwidth=2,bg="gray",justify=C ENTER,relief=SUNKEN) 10 rotulo.pack() 11 12 self.button = Button(frame, text="Sair", fg="red", command=frame.quit,borderwidth=1) 13 self.button.pack(side=LEFT) 14 self.hi_there = Button(frame, text="Gerar Numero", command=self.say_hi,borderwidth=1) 15 self.hi_there.pack(side=RIGHT,padx=2,pady=2) 16 17 def gera_seis(self): 18 a = {} 19 for i in range(6): 20 a[i] = "%02d" % int (random.randint(0,60)) 21 resultadoA = "%s-%s-%s-%s-%s-%s" % (str(a[0]),str(a[1]),str(a[2]),str(a[3]),str(a[4]),str(a[5])) 22 return resultadoA 23 24 def say_hi(self): 25 resultado = self.gera_seis() 26 raiz = Tk() 27 F = Frame(raiz) 28 F.pack() 29 hello = Label(F, text=resultado) 30 hello.pack() 31 F.mainloop() 32 33 root = Tk() 34 root.title("$$$ Loteria $$$") 35 app = App(root) 36 root.mainloop() -- Djames Suhanko LinuxUser 158.760

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Re: f.seek() unwanted output
by thomasvangurp＠gmail.com Jan. 5, 2009

Jan. 5, 2009

Hi Tim, works! thanx a lot Thomas

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structuring a package?
by Torsten Mohr Jan. 5, 2009

Jan. 5, 2009

Hi, i have a question on how to structure a package best, would be great if anybody could give me some hint on this: Assuming i have a base class GraphicObject and derived from that some classes like Square, Circle, ... It looks natural to me to write in a code that uses the package: import graphic import graphic.square import graphic.circle That way i'd have to structure the code like this: graphic/ __init__,py (GraphicObject) square.py (Square) circle.py (Circle) Does that make sense like this? Are there better ways to structure things in Python? One thing that bothers me is that when i write in circly.py something like "import graphic", then i can't have the test code for the Circle within circle.py, at least it looks to me like this. The closest thing that handles this issue that i could find was PEP 328, but it doesn't cover this problem. Thanks for any hints, Torsten.

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Re: structuring a package?
by Torsten Mohr Jan. 5, 2009

Jan. 5, 2009

Hello James, >> That way i'd have to structure the code like this: >> >> graphic/ >> __init__,py (GraphicObject) >> square.py (Square) >> circle.py (Circle) >> >> Does that make sense like this? > > This seems perfectly acceptable. Thanks for that hint. Do you see a way that i could write in circle.py: circle.py: import graphic class Circle(graphic.GraphicObject): ..... if __name__ == '__main__': abc = Circle() abc.some_test_code() Thanks for any hints, Torsten.

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fetch image
by asit Jan. 5, 2009

Jan. 5, 2009

import httplib class Server: #server class def __init__(self, host): self.host = host def fetch(self, path): http = httplib.HTTPConnection(self.host) http.request("GET", path) r = http.getresponse() print str(r.status) + " : " + r.reason server = Server("www.python.org") fp=open("phpvuln.txt") x=fp.readlines(); for y in x: server.fetch("/" + y); The above code fetches only the html source of the webpage. How to get the image, flash animation and other stuffs ????

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Re: why cannot assign to function call
by Marc 'BlackJack' Rintsch Jan. 5, 2009

Jan. 5, 2009

On Sun, 04 Jan 2009 22:55:09 -0600, Derek Martin wrote: > On Sun, Jan 04, 2009 at 09:30:20PM -0500, Steve Holden wrote: >> > I'm going to go out on a limb and assert that there's NO POSSIBLE WAY >> > a student could intuit Python's variable assignment behavior, having >> > never been exposed to that same behavior prior. It needs to be >> > taught. >> > >> As does assignment of any kind. > > I'm not sure that's true. Having taken algebra prior to learning Basic, > I intuitively understood what this program would do when I executed it, > the first time I saw the code, and before I read the explanation: > > 10 let x = 10 > 20 print x Do you really thought of `x` as a named memory location where the bit pattern for the floating point value 10 is stored, with just the algebra knowledge!? Isn't "Ah there the name `x` is bound to the value 10." more likely? As it is the technically easier and IMHO more intuitive explanation when you go from math to programming. > [Well, to be honest it's been a very long time since I've programmed in > Pet BASIC, and the syntax may be wrong. The point is, just as I did > then, I am positive that you intuitively understand what the above is > intended to do, even if it is not valid BASIC syntax -- because if you > did not, we would not be having this discussion.] Syntax is correct. :-) The ``let`` is optional in Commodore BASIC. But where is the difference to x = 10 print x ? Wouldn't you have guessed what this Python program will do just the same? Ciao, Marc 'BlackJack' Rintsch

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How to "kill" orphaned threads at program exit
by Giampaolo Rodola' Jan. 5, 2009

Jan. 5, 2009

Hi, I know that it's not possible to "kill" threads but I'm wondering if does exist some workaround for my problem. I have a test suite which does a massive usage of threads. Sometimes happens that one test fails, the test suite keeps running until the end, and when it's finished the program hangs on and the only way to stop is to kill it manually. I noticed that, at the end of the program, I can call threading.enumerate() and see the pending thread objects: def test_main(): ... start_suite() print threading.enumerate() I was wondering if I can do anything with that. I took a look at test/test_support which has threading_setup() and threading_cleanup() functions. Could such functions be useful to me? Thanks in advance, --- Giampaolo http://code.google.com/p/pyftpdlib/

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Re: why cannot assign to function call
by Marc 'BlackJack' Rintsch Jan. 5, 2009

Jan. 5, 2009

On Sun, 04 Jan 2009 20:03:11 -0600, Derek Martin wrote: > On Sat, Jan 03, 2009 at 10:15:51AM +0000, Marc 'BlackJack' Rintsch > wrote: >> On Fri, 02 Jan 2009 04:39:15 -0600, Derek Martin wrote: >> >> What's the difference between Python and Java or C# here!? Or are they >> also "BIZARRE"!? > > I am happily ignorant of C#. As for Java, take the following code: > > a = 6; > a = 5; > > In Python, when you execute the equivalent code, it causes two different > objects to spring into existence, the first of which may be cleaned up > by the GC (except that since we're using small integers, that's not > likely to happen). Unless I'm misinformed (which is very possible, my > experience with Java has been extremely limited) in Java that's not the > case... the storage is allocated to the name a when you execute its > declaration, and the *same storage* is reused upon subsequent > assignment. > > That behaves exactly like named bins. So does the equivalent in Python. Or to see it the other way: In both languages it *behaves* like (re)binding the name `a` to two different objects. So it is an implementation detail. Even a Python implementation could reuse the same memory location to store the two numbers. >> > And for that matter, it's pretty unintuitive generally. >> >> Names and objects are quite "natural" IMHO. There are many real world >> objects which we attach one or more names to, or refer to in sequences >> like "please give me the third book on that shelve" (``shelve[2]``). > > Indeed, but the way we assign names to them does not behave as it does > in Python. In what way? >> I think the "bin model" is more complex because you don't just have a >> name and an object but always that indirection of the "bin". > > I cheerfully disagree. :) "Named bins" is essentially how algebra > works, No it isn't. Mathematics is about binding names and not about putting values into bins. And a mathematical variable can't be rebound once you assigned a value to it. The "intuitive" model for people with a math background would be that of functional languages like Haskell, which is even more strange for people used to "named bins" than the Python, Java, Ruby, … approach. > and how several generations of computer languages, not to mention > the actual machine language those generated, behaved, before the current > crop. Those interpretations came first, because, much as in the > evolution of any other science, that was the model which was most > intuitive or easily explained. In terms of the underlying machine, but that is exactly what I meant by the additional indirection of the bins. You just have to drag the low level named bins into the explanation because it is an implementation detail of the languages. And there where always languages that use a model like Python parallel to the "named bins languages", it is nothing new. Ciao, Marc 'BlackJack' Rintsch

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cx_Oracle issues
by huw_at1 Jan. 5, 2009

Jan. 5, 2009

Hey all. When using cx_Oracle to run a procedure like: cursor.execute("select (obj.function(value)) from table where id=blah") I am getting the following error: ORA-06502: PL/SQL: numeric or value error: character string buffer too small ORA-06512: at line 1 Looking at cursor.description I get: [('(obj.function(value))', <type 'cx_Oracle.STRING'>, 4000, 4000, 0, 0, 1)] Any tips - i have never seen this error before but am guessing that the value being returned is too big for the buffer size set for the cursor. the procedure fetches data from a LOB. Any suggestions/confirmations? Many thanks

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