Re: What's The Best Editor for python
On 2006-03-26, Andrew Gwozdziewycz [EMAIL PROTECTED] wrote: If you want something that won't get in your way, you should really use /bin/ed. It's probably simpler to use then searching the archives. /bin/ed will also run in cygwin for windows. Can one of you say to me what's the best editor for editing the python programs( for linux or windows ) The best editor is the one you like best. I'm a vim user with taglist--I'm not fully happy with how ctags does Python, but it's more than Good Enough. But editors are religious, and not worth arguing about, generally. -- http://mail.python.org/mailman/listinfo/python-list
Want to re-pack() a Frame displaying a collection
List, I'd like to do the following with Tkinter's Frame() object: 1. Display a collection of pack()-able objects. Easy. Done. I hold the objects in a dictionary, mostly so that the owning program can refer to them uniformly. 2. Whenever the collection is added to or deleted from, re-pack() the owning object. Will this happen automatically simply whenever I add or delete from the object's __dict__, or do I need to add to __setattr__ and __delattr__ to detect when the user has added or removed an object? Thanks Not Quite Related: I'm doing a lot of displaying of (Label, Entry) pairs so I've another subclass of Frame() that simplifies that action for me. These are items from a collection that's created at runtime where the labels aren't known in advance. Right now, I'm raising an exception if grid() or place() is called on the object. Eventually, what I'd like to do is flesh out the grid() and place() methods so that the Label and Entry are placed in what I think are sensible default positions reletive to the desired placement. With grid(), how do I determine my current column and row in the case when grid() is invoked without arguments? With place() . .pretty much the same song. I need to determine my position so that I can Do The Right Thing (or at least the expected thing). Thanks -- http://mail.python.org/mailman/listinfo/python-list
Re: is there a better way?
On 2006-02-11, Alex Martelli [EMAIL PROTECTED] wrote: [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: Problem: You have a list of unknown length, such as this: list = [X,X,X,O,O,O,O]. You want to extract all and only the X's. You know the X's are all up front and you know that the item after the last X is an O, or that the list ends with an X. There are never O's between X's. If the list is incredibly long, you should use a bisection approach. Standard module bisect in the Python library could help, but mostly as an _example_, since it unfortunately relies on normal alphabetic order, and alphabetically speaking X should come _after_ O, not _before_. Isn't every call to list.index() an O(n) operation? We certainly want to avoid multiple calls there if we can. What happens if your split occurs in the middle of your block of Xs? Then the split before/after fails --the stated algorithm says, If the split is an X, choose the front half, so perhaps the statement was inprecise? The only way you'll know if you have an X in a particular block is using a linear search method, either in Python or with list.index() If (as the OP seemed to state) we KNOW that there's only one block of X's in the list: 1. Find the index of the first X 2. Find the index of the last X. 3. Delete the block we've found. That relies on the underlying language, which means we're working in Linear Time in C, more or less. If we make no such guarantee, then I can do the operation in linear Python Time by scanning the list once, finding each instance and calling list.del() as I find each block, keeping track of my current position so I don't have to start over again. Judging from way the OP worded the question, I'd advise making something that works and that you understand how it works. After that, s/he can worry about whether or not its performance is suboptimal. How large must the list be before logarithmic Python algorithm is faster than linear C algorithm? I've never measured, but it may be a question worth exploring if one has a huge pile of data to chew on--like US Census or UN budget-sized. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there any books such as 'effective python' or else about the performance?
On 2006-02-11, Kenneth Xie [EMAIL PROTECTED] wrote: att, thx. A lot of the ideas discussed in Effective C++ et al are things that Python does for us already. C++ works at a much lower layer of abstraction and you need to deal explicitly with freestore for any nontrivial class. EC++ is mostly about how NOT to crash your programs. The Python Cookbook is a more pythonic version of the same idea--proven techniques appropriate to the abstraction level of the language. Design Patterns is worth reading as well, but be careful with it. Many of the ideas that are difficult to do in C++, Java, Smalltalk, etc (singletons come to mind) are trivially easy to do in Python because of how our object model works. Bruce Eckle's Thinking in Python gives a pattern introduction explaining how things work in Python that can give you a sprinboard to adapting other patterns from C++ et al. -- http://mail.python.org/mailman/listinfo/python-list
Re: Another try at Python's selfishness
On 2006-02-08, Ben Wilson [EMAIL PROTECTED] wrote: But the point is, the current situation is not newbie-friendly (I can tell, I am a newbie) I will agree to that, as I consider myself still new. _But_, it's a stumbling stone only briefly. Get enough nagging error messages, and you learn and move on. I agree with the grandparent poster that it is a perfect self-documenting thing, as the use of 'self' is pretty obvious. For a language that one can learn in a short time, this is a tempest in a teacup. This old C hound finds it much more sensible than C++ or Java, where the self parameter (called this) is implicit rather than explicit and you just sorta kinda hafta know it's there and the correct syntax to use to reference it. Then there's all the places where you need a Secret Decoder Ring--in Java you have to define the equivalents of stdout and stdin as they aren't provided. In c++ you can't overload the operator in your class, you have to use a friend function and you have to return an ostream--the Rule of Three for constructors, and just generally lots of small knotty issues to bite beginners. 9 times out of 10, Python Just Works the first time and things do what your mind says they should without having to learn a seventeen special cases to everything. IMO, YMMV, Not Valid in Vermont, Happy Fun Ball may accellerate to dangerous speeds. Do NOT taunt Happy Fun Ball. -- http://mail.python.org/mailman/listinfo/python-list
Re: breadth first search
On 2006-02-08, News [EMAIL PROTECTED] wrote: I am new in using Python Anyone know how to implement breadth first search using Python? Can Python create list dynamically, I want to implement a program which will read data from a file and store each line into a list, is this possible? Please send mail to me at [EMAIL PROTECTED] or reply this mail Thanks a lot! Yes. List has methods that support a stack, in case you find it useful in this context. Yes. List has methods that allow dynamic creation, such as might be useful when implementing a stack, in case you find it useful in this context. And Yes. File has methods that will populate a list from a file. Examples are in the tutorials. You're welcome. You can find numerous examples of the breadth-first algorithm on the web. You can then take the individual steps and translate them into Python. You'll likely find one or two sticking points, but the implementation is straightforward from pseudocode or from a GOOD statement of the algorithm. -- http://mail.python.org/mailman/listinfo/python-list
Re: Having Trouble with Scoping Rules
On 2006-01-31, Fredrik Lundh [EMAIL PROTECTED] wrote: def ExpensiveObject(): global _expensiveObject if _expensiveObject is None: _expensiveObject = A VERY Expensive object print CREATED VERY EXPENSIVE OBJECT return _expensiveObject if __name__ == __main__: print _expensiveObject print ExpensiveObject() print ExpensiveObject() print ExpensiveObject() which prints None CREATED VERY EXPENSIVE OBJECT A VERY Expensive object A VERY Expensive object A VERY Expensive object and works perfectly fine if you import it from another module: Ah, I had another error that broke it on import. Testing with a dictionary showed me the creates another object error. Using a string constant for that was just a between the ears problem that would have shown me the error much quicker. Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: Costly object creation (was : Having Trouble with Scoping Rules)
On 2006-01-31, bruno at modulix [EMAIL PROTECTED] wrote: See other answers in this thread for how to solve the UnboundLocalError problem. Now about your *real* problem - which is nothing new -, you may want to read about some known solutions: http://en.wikipedia.org/wiki/Singleton_pattern http://en.wikipedia.org/wiki/Proxy_pattern http://en.wikipedia.org/wiki/Lazy_initialization http://en.wikipedia.org/wiki/Memoization No, I'm already quite certain that this is a Singleton--pythonically a module-level instance of Something--I'm not thinking of it as lazy instantiated 'cuz it's initialized at startup, but I suppose it qualifies. I considered using a Borg for this, but discarded the idea as too complicated for my needs--this will be easier to implement . . . Which I suppose it would be if I knew how correctly to use the global keyword. I don't need to restrict the actual class to One Instance so much as I'd prefer that to be the default behavior. I can't think of a reason why I'd want to subclass this, so I can't say whether it makes sense to Borg/Highlander/Singleton it or not. For now, I'll Do The Simplest Thing That Might Work and figure YAGNI (or IAGNI, I guess). Thanks for the help. -- http://mail.python.org/mailman/listinfo/python-list
Having Trouble with Scoping Rules
List: I've a module that's not doing what I expect. My guess is that I don't quite understand the scoping rules the way I should. I have an object that's costly to create. My thought was to create it at the module level like this: # expensive Object Module _expensiveObject = None def ExpensiveObject(): if not(_expensiveObject): _expensiveObject = A VERY Expensive object return _expensiveObject if __name__ == '__main__': print _expensiveObject print ExpensiveObject() When I run this module, I get the expected None but then I get UnboundLocalError from the function call when _expensiveObject is accessed: Traceback (most recent call last): File C:\Python24\Lib\site-packages\pythonwin\pywin\framework\scriptutils.py, line 310, in RunScript exec codeObject in __main__.__dict__ File Expensive.py, line 13, in ? print ExpensiveObject() File Expensive.py, line 6, in ExpensiveObject if not(_expensiveObject): UnboundLocalError: local variable '_expensiveObject' referenced before assignment I obviously missed some part of the scoping rules. What's the correct way to do this? Thanx Charles -- http://mail.python.org/mailman/listinfo/python-list
Re: Having Trouble with Scoping Rules
On 2006-01-31, Farshid Lashkari [EMAIL PROTECTED] wrote: You need to declare _expensiveObject as global inside your function. Whenever you assign something to a variable that resides in the global scope inside a function, you need to declare it as global at the beginning of the function. So your function should look like this def ExpensiveObject(): global _expensiveObject if not(_expensiveObject): _expensiveObject = A VERY Expensive object return _expensiveObject The documentation will no doubtedly explain it better than I have Not really. If I'd understood the docs, I wouldn't need to ask here. Okay, that works in the module where I define the function. But if I import the module: # expensive Object User import Expensive print Expensive.ExpensiveObject() I get the same exception. That approach most likely isn't going to work for me, as I need to be able to reuse the costly (to create) object. Okay THIS seems to be working for me: # expensive Object Module _expensiveObject = None def ExpensiveObject(): try: retval = _expensiveObject except UnboundLocalError: _expensiveObject = A VERY Expensive object retval = _expensiveObject return retval if __name__ == '__main__': print _expensiveObject print ExpensiveObject() Which gives me: import Expensive a = Expensive.ExpensiveObject() b = Expensive.ExpensiveObject() a == b True a is b True I'll try it with my actual class instance to verify. Anyone see anything I'm missing? Thanx -- http://mail.python.org/mailman/listinfo/python-list
Re: How do I tell if I'm running in the PyWin interpreter?
On 2006-01-28, Peter Otten [EMAIL PROTECTED] wrote: Charles Krug wrote: Is there a way to detect that I'm running the the PyWin interpreter so that I can bypass its raw_input behavior? You could test if pywin_specific_module in sys.modules: # use workaraound Or maybe you can get away with always using sys.stdin.readline() instead of raw_input()? Look into cmd.py for an example. Peter cmd.py is the battery included I was thinking of last night. Unfortunately it uses something that PyWin replaces. However I did note that PyWin's version raises KeyboardInterrupt out of its dialog box. That's not ideal, but at least it gives me an idea what I need to trap to exit. -- http://mail.python.org/mailman/listinfo/python-list
Re: How do I tell if I'm running in the PyWin interpreter?
On 2006-01-28, Charles Krug [EMAIL PROTECTED] wrote: On 2006-01-28, Peter Otten [EMAIL PROTECTED] wrote: Charles Krug wrote: Is there a way to detect that I'm running the the PyWin interpreter so that I can bypass its raw_input behavior? You could test if pywin_specific_module in sys.modules: # use workaraound Or maybe you can get away with always using sys.stdin.readline() instead of raw_input()? Look into cmd.py for an example. Peter cmd.py is the battery included I was thinking of last night. Unfortunately it uses something that PyWin replaces. However I did note that PyWin's version raises KeyboardInterrupt out of its dialog box. That's not ideal, but at least it gives me an idea what I need to trap to exit. Okay, I poked around a bit more and found the initialization code that does this: sys.modules['__builtin__'].raw_input=Win32RawInput Which is the substituted function. Is there a way to access the original function that I want to use, or do I need to come up with some other way to do console input? Thanks -- http://mail.python.org/mailman/listinfo/python-list
How do I tell if I'm running in the PyWin interpreter?
Here's the deal: I've a dead-simple command-line program I'm using to test things that I can't (for various reasons) test in the IDE. Here's a do-nothing subset that shows the idea: # insanely simply command interpreter import Commands import sys myPrompt = '$ ' # Raw Input doesn't QUITE do what I want in Python Win. while True: try: args = raw_input(myPrompt).strip().split() except EOFError: break cmd = args[0] print '%s' % cmd print args As the comment says, when I run this under Python Win, I get an (pretty sure) Tkinter interface, not a command line, and I don't get my EOFError when I expect to. This is something I occasionally need in my Swiss Army Knife. Not often, but when I need something like this, I need something like THIS pretty badly, and sometimes I need to run it under PyWin (and under Linux, Unix, Solaris, and anything else you might name and a few things I bet you couldn't). Is there a way to detect that I'm running the the PyWin interpreter so that I can bypass its raw_input behavior? Is there a simpler way to do this? I recall some sample code that did something very much like this (define a small set of callbacks and execute them from a command-like interface) but I can't seem to lay my hands on the example. Thanx Charles -- http://mail.python.org/mailman/listinfo/python-list
Re: How do I tell if I'm running in the PyWin interpreter?
On 2006-01-28, Steven D'Aprano [EMAIL PROTECTED] wrote: As the comment says, when I run this under Python Win, I get an (pretty sure) Tkinter interface, not a command line, and I don't get my EOFError when I expect to. When do you expect to get an EOFError? The only way I get an EOFError is if I explicitly hit Ctrl-D while raw_input is running. When do you expect to get it? Have you tried Ctrl-Z under Windows? That's exactly how I use it everywhere else. Type until you're done then hit Ctrl-D The problem is only when running under the PyWin IDE . . I'd been using this for months under Idle and every place else I needed it. The problem is that PyWin doesn't give you a raw command line with in response to raw_input, but gives you a text entry box and a nice OK-Cancel yada yada interface that silently eats my EOF. I'd like to have a single tool I can use everywhere. So far as I can tell, that means I have to detect the PyWin IDE and handle it separately on initialization so I get a real raw input and not the redefined Tkinter version. -- http://mail.python.org/mailman/listinfo/python-list
Re: Trying to generate a list of the subclasses of C
On 2006-01-16, Alex Martelli [EMAIL PROTECTED] wrote: Charles Krug [EMAIL PROTECTED] wrote: ... I'm trying to create a list of all of C's subclasses: There's a class method for that very purpose: class C(object): pass ... class D(C): pass ... class E(C): pass ... C.__subclasses__() [class '__main__.D', class '__main__.E'] Alex Exactly what I was looking for, thanks. It stuck in my brain that there was a way to do this, but I couldn't lay my mouse on it. -- http://mail.python.org/mailman/listinfo/python-list
Trying to generate a list of the subclasses of C
List:
I have this:
# classC.py
class C(object): pass
class D(C): pass
class E(C): pass
def CSubclasses():
for name in dir(): pass
I'm trying to create a list of all of C's subclasses:
import classC
print C
aList = []
for name in dir(classC):
print name,
try:
if issubclass(classC.__dict__[name], C):
print classC.__dict__[name]
else:
print
except TypeError:
print
Which gives me this:
class '__main__.C'
C
CSubclasses
D
E
__builtins__
__doc__
__file__
__name__
However when I do this from the command line:
issubclass(D,C)
True
but
issubclass(classC.__dict__['D'], C)
False
So my approach is flawed.
The end result I'm after is an automatically generated dictionary
containing instaces of the subclasses keyed by the subclass names:
{'D':D(), 'E':E(), . . . }
I can see the information I need in the module's __dict__ and by using
the dir() method, but I'm not having much success extracting it.
--
http://mail.python.org/mailman/listinfo/python-list
Re: File Paramaterized Abstract Factory
On 2006-01-11, Fredrik Lundh [EMAIL PROTECTED] wrote: Charles Krug wrote: What I'd like is to do something like this: factoryFile = sys.argv[1] # we assume that argv[1] implements a # correct ThingMaker interface. sys.argv[1] is a string, so I assume that you meant to say that the module named by argv[1] implements the correct interface. Yes. Anywho, my problem is with the whole Miracle thing. I've tried using __import__: a = 'HerFactory' __import(a) Which returns: module 'HerFactory' from 'HerFactory.py' try: factoryObject = __import__(factoryFile) print dir(factoryObject) Ah Ha! That's what comes of working from memory instead of letting the computer remember for me. factoryFile = 'ThingMaker' factoryObject = __import__(factoryFile) print dir(factoryObject) ['MakeOtherThing', 'MakeThing', '__builtins__', '__doc__', '__file__', '__name__'] factoryObject.MakeThing() I made a Thing! Wonderful! Exactly what I'm after, thanks. this should give you a list of the functions in the given module, or an ImportError if it doesn't exist. Yes, that's what I was getting. Should have pasted that as well, but I was feeling grumpy and impatient. Thanx Charles -- http://mail.python.org/mailman/listinfo/python-list
File Paramaterized Abstract Factory
List: I have an idea for an abstract factory that parameterizes the factory with an input module. The general ideom can be expressed thus: class ThingFactory(object): def CreateThisThing() : return ThisThing() def CreateThatThing() : return ThatThing() def CreateTheOtherThing() : return TheOtherThing() With subclasses: class HerThingFactory(ThingFactory): def CreateThisThing() : return HerThisThing() # etc You'd invoke it in the usual way: ThingClient(Factory=ThingFactory) And Thing client would refer to: ThingFactory.CreateThisThing() Now, Pythonically speaking, as the envisioned application uses only one ThingFactory at a time, I'd ordinarily want to just load a module (HisFactory, HerFactory, KidsFactory, YadaYadaYadaFactory) that implements the expected interface--in this case, supplying the CreateX methods. What I'd like is to do something like this: factoryFile = sys.argv[1] # we assume that argv[1] implements a # correct ThingMaker interface. # A Miracle Occurs Here UseFactory(factoryObject) Where UseFactory looks like: def UseFactory(factoryObject): factoryObject.CreateThisThing() # returns the kind of thing Rather a lot of preamble to learn what I'm trying to do. Anywho, my problem is with the whole Miracle thing. I've tried using __import__: a = 'HerFactory' __import(a) Which returns: module 'HerFactory' from 'HerFactory.py' But after that I can't access the members. Clearly I'm missing a step or seventeen. What's the best way to do this? Thanks Charles -- http://mail.python.org/mailman/listinfo/python-list
Re: Python's Performance
On Mon, 10 Oct 2005 11:21:18 -0700, Donn Cave [EMAIL PROTECTED] wrote: Iron- Python). is it still an interpreter if it generates machine code? Is what an interpreter? I am not very well acquainted with these technologies, but it sounds like variations on the implementation of an interpreter, with no really compelling distinction between them. An important point made by Tannenbaum is this: Once you have a machine that executes instructions (what he called hardware or Level Zero Machine, then you can create higher level machines that execute code written in the language of that machine. For the purposes of writing C, for example, we pretend that we have this magical machine that runs C code, or more typically, the machine that runs (insert OS name) C code. When the Level n machine isn't fast enough, we go to the level n-1 machine . . . C or Java for us, or assembly, but the model remains valid until the point where you bump up against the underlying logic gates. While we don't talk about the Virtual Machine the way Java folks do, Tannenbaum's model is still useful for thinking about such things. -- http://mail.python.org/mailman/listinfo/python-list
Re: When someone from Britain speaks, Americans hear a British accent...
On Mon, 10 Oct 2005 15:46:34 -0500, Terry Hancock [EMAIL PROTECTED] wrote: On Saturday 08 October 2005 04:35 am, Steve Holden wrote: I must have been working at NASA at the time; they are well known for embiggening prices. Not nearly as much as the DoD, from what I hear. Truthfully, I think those stories are bit exaggerated -- I think the real problem is somebody making a bad make/buy decision. They decide to make something that they could easily have bought at the hardware store. Typically, it was a $30 hammer with $270 worth of paperwork attached. The famous $10k Toilet Seat is actually a bit of an interesting tale. The part in question is the toilet from a C5A transport . . not something you can purchase at the local Home Depot. Being an aircraft toilet, it's crammed into a tiny space and has to be as light as possible and all the things you associate with aircraft toilets. When they were speccing the project, the airframe manufacturer included some number of spare toilet seats in the bid, given the expected life of the airframe. Some faceless bureaucrat decided that they didn't NEED any spare toilet seats and cancelled that line item. Lo and Behold, they eventually needed spare toilet seats. But because of Another Good Regulation (tm) the tooling had been recycled. Recreating the tooling to make the spares was, amortized over the number ordered, around $10k/seat. Compared to the tooling costs, subsequent orders of the same seat are pretty much free . . . at least until some bozo in Ring A decides to toss the tooling again. -- http://mail.python.org/mailman/listinfo/python-list
Re: Creating a list of Mondays for a year
On Mon, 19 Sep 2005 12:10:04 GMT, Chris [EMAIL PROTECTED] wrote: Thanks to everyone for your help! That fit the need perfectly. In article [EMAIL PROTECTED], [EMAIL PROTECTED] says... Is there a way to make python create a list of Mondays for a given year? For example, mondays = ['1/3/2005','1/10/2005','1/17/2005','1/24/2005', '1/31/2005','2/7/2005', ... ] You can also calculate it using the Julian Day Number. Google on astronomical calculations, or read the introduction to one of the Numerical Recipies. . . books for a discussion and algorithm. -- http://mail.python.org/mailman/listinfo/python-list
Re: How to program efficient pattern searches in a list of float numbers?
On 19 Sep 2005 00:02:34 -0700, malv [EMAIL PROTECTED] wrote: Simple case: In this list, how to find all occurences of intervals of n adjacent indexes having at least one list-member with a value between given limits. Visualizing the list as a two-dimensional curve, this is like horizontally dragging a given rectangle over the curve and finding the x coordinates where the curve passes through the rectangle.(Define such a x-index coordinate as the left corner of the rectangle.) More complicated case: Given a pair of rectangles spaced relatively to each other in a fixed manner. Drag this rectangle pair horizontally over the above two-dimensional curve and list the indexes of the occurences where the curve passes simultaneously through both rectangles. (Define such a x-index coordinate as the leftmost corner of the rectangle pair). These problems can be solved by programming a naive search advancing index by index. It seems obvious that due to the localized properties searched for, much more efficient searches should be possible. After having found the occurence-indexes for one particular rectangle set, how to find the pattern occurences after changing one or more rectangle parameters? Make a picture of the problem. From your description, I'm not certain anything more complicated than a linear search is called for. Is this the phrasing of the original problem presentation? Seems to me the word superimpose ought to occur here. Another thought: What is the end result you're after? Often we start thinking of a solution but lose sight of the end result. Then another solution will pop into our mind that makes it Oh So Simple. -- http://mail.python.org/mailman/listinfo/python-list
Re: Having trouble importing against PP2E files
On Fri, 08 Jul 2005 22:43:55 +0300, Elmo Mäntynen [EMAIL PROTECTED] wrote: -BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Import Error: no module named PP2E.launchmodes However if I copy launchmodes.py into my work directory, it imports successfully. Both Examples above and Examples\PP2E contain the __init__.py file. Are both Examples and PP2E packages? They appear to be, yes. In python if a folder is meant to represent a package it should iclude the above mentioned file __init__.py and by saying the above your suggesting that PP2E is a package inside the package Examples. That appears to be the case, yes. If the above is correct, you should append the pythonpath with c:\Python24\ and refer to the wanted .py with Examples.PP2E.launchmodes. As such the import statement obviously should be from Examples.PP2E.launchmodes import PortableLauncher. If the above isn't the case and there is still something unclear about this, reply with a more detailed post about the situation. The registry value is this: C:\Python24\Lib;C:\Python24\DLLs;C:\Python24\Lib\lib-tk; C:\Python24\Examples\PP2E I'm not realy sure what other details are relavant. I've installed from the Windows .msi package, and appended the directory I want to PythonPath in the registry, and that doesn't do what I need. This is WinXP Pro -- http://mail.python.org/mailman/listinfo/python-list
Having trouble importing against PP2E files
List: I'm trying to use the example files from Programming Python, 2nd Ed. I've copied them into c:\Python24\Examples\PP2E. Launching any of the examples programs by themselves seems to work spiffily. Using regedit, I appended c:\Python24\Examples\PP2E to Pythonpath from the immediate window, executing the line: from PP2E.launchmodes import PortableLauncher Raises the exception: Import Error: no module named PP2E.launchmodes However if I copy launchmodes.py into my work directory, it imports successfully. Both Examples above and Examples\PP2E contain the __init__.py file. Obviously, I'm missing a setup step here. What magic do I need to perform to get Python to find modules in the Examples heirarchy? Is there any way to check from the immediate window where Python will search for modules? Pythonpath appears to be correct, but the file isn't importing unless I copy it to the current directory. Thanx Charles -- http://mail.python.org/mailman/listinfo/python-list
Re: Excellent Site for Developers
On Sat, 25 Jun 2005 14:50:48 GMT, Brian [EMAIL PROTECTED] wrote: Do Re Mi chel La Si Do wrote: rather... super troll 100% Agreed. Can anyone say, This looks like spam... Feels like spam... and is about as useful here in the Python forums as spam -- therfore my conclusion is that his VB message probably IS SPAM. :-D Brian --- H . . .tough call. After all, Spam is nearly ALWAYS ON topic for a Python group. *enjoys his spam bacon eggs spam spam and spam* -- http://mail.python.org/mailman/listinfo/python-list
Re: Python choice of database
On Mon, 20 Jun 2005 23:42:21 -0800, EP [EMAIL PROTECTED] wrote: Oren suggested: How about using the filesystem as a database? For the number of records you describe it may work surprisingly well. A bonus is that the database is easy to manage manually. I tried this for one application under the Windows OS and it worked fine... until my records (text - maybe 50KB average) unexpectedly blossomed into the 10,000-1,000,000 ranges. If I or someone else (who innocently doesn't know better) opens up one of the directories with ~150,000 files in it, the machine's personality gets a little ugly (it seems buggy but is just very busy; no crashing). Under 10,000 files per directory seems to work just fine, though. For less expansive (and more structured) data, cPickle is a favorite. Related question: What if I need to create/modify MS-Access or SQL Server dbs? -- http://mail.python.org/mailman/listinfo/python-list
Re: Loop until condition is true
On Tue, 21 Jun 2005 12:05:25 +0200, Magnus Lycka [EMAIL PROTECTED] wrote: Remi Villatel wrote: while True: some(code) if final_condition is True: break # # What I don't find so nice is to have to build an infinite loop only to break it. This is a common Python idiom. I think you will get used to it. Is there a better recipe? final_condition = False while not final_condition: some(code) To the OP, don't get hung up on the syntax we use to implement a loop. I took my first programming class long enough ago that we had to do things like this (roughly translating the FORTRAN IV I remember into p-code) To do: while TrueCondition (loop body) we'd have to write: TopOfLoop: if not TrueConditional goto loopEnd (loop body) goto TopOfLoop loopEnd: We were even required to write our source twice: The first pass was structured and had to be proven correct. The second pass was translated into something our compiler supported. We still called it a while loop even though the syntax was icky. When C came out with its built in looping, it was an unbelievable luxury. -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there something similar to ?: operator (C/C++) in Python?
On Mon, 20 Jun 2005 06:36:42 GMT, Ron Adam [EMAIL PROTECTED] wrote:
Ron Adam wrote:
You might be able to use a dictionary of tuples.
call_obj = {(type_obj1,0):obj1a,
(type_obj1,0):obj1b,
(type_boj2,1):obj2a,
(type_obj2,1):obj2b,
etc... }
call_obj[(type_of_obj,order)]()
Regards, Ron
This won't work like I was thinking it would.
But to get back to your is there a ? operator question...
Try this.
def foo():
return foo
def boo():
return boo
print (foo, boo)[10]()# prints boo
print (foo, boo)[10]()# prints foo
Regards,
Ron
Another thought:
Often complicated conditional logic is a flag that we need to refactor.
An accounting package I built has an official list of approved vendors,
but allows users to provisionally add a new vendor, which is corrected
later.
The bulk of this system only understands, This document has-a vendor
with a vendor factory that returns the appropriate type of vendor.
All of the logic specific to the specific subclass is internal to the
subclasses themselves.
--
http://mail.python.org/mailman/listinfo/python-list
Couple functions I need, assuming they exist?
List: First, I'm reading that aString.split() is depreciated. What's the current best practice for this? Or am I mistaking that: myWords = split(aString, aChar) is depreciated but myWords = aString.split(aChgar) is not? Second question, I've written a script that generates a LaTeX source containing randomly generated arithmetic problems of various types. The target of the problems (my daughter) would prefer that the thousands be delimited. Is there a string function that does this? Thanks Charles -- http://mail.python.org/mailman/listinfo/python-list
Re: Couple functions I need, assuming they exist?
On 20 Jun 2005 15:51:07 GMT, Duncan Booth [EMAIL PROTECTED] wrote: Peter Hansen wrote: The target of the problems (my daughter) would prefer that the thousands be delimited. Is there a string function that does this? You refer to something like putting a comma between groups of three digits, as in 1,000? This is locale-specific, and there's a locale module that should have what you need. import locale locale.setlocale(locale.LC_ALL, '') 'English_United Kingdom.1252' print locale.format(%d, 100, True) 1,000,000 Perfect! Thanks. Sometimes hard part is figuring out which package already does the thing I need done. Charles. -- http://mail.python.org/mailman/listinfo/python-list
Re: performance of Nested for loops
On 20 May 2005 15:35:10 -0700, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: Is there a better way to code nested for loops as far as performance is concerned. what better way can we write to improve the speed. for example: N=1 for i in range(N): for j in range(N): do_job1 for j in range(N): do_job2 What do you see when you profile the code? Premature Optimization is the root of all manner of evil and all that good stuff. -- http://mail.python.org/mailman/listinfo/python-list
Re: How to detect a double's significant digits
On 5 May 2005 10:37:00 -0700, mrstephengross [EMAIL PROTECTED] wrote:
Hi all... How can I find out the number of significant digits (to the
right of the decimal place, that is) in a double? At least, I *think*
that's what I'm asking for. For instance:
0.103 -- 3
0.0103 -- 4
0.00103 -- 5
0.000103 -- 6
0.103 -- 7
Thanks in advance!
--Steve ([EMAIL PROTECTED])
I would say that each of these examples has three signficant figures.
Each of them can be expressed as:
1.03e+n
For any integer n.
The fact that you've only shown the cases where n \in {-1, -2, -3, -4,
-5 . . } doesn't change the generality of the answer.
--
http://mail.python.org/mailman/listinfo/python-list
Has anyone built a file reader for NIST IHEad?
List: I'm playing with some image algorithms and one of the examples discusses fingerprint comparison. The NIST has fingerprint sample files for download, in NIST IHead format. Has anyone built a reader for that format? Thanks Charles -- http://mail.python.org/mailman/listinfo/python-list
Re: OOP
On 28 Apr 2005 10:34:44 -0700, [EMAIL PROTECTED] [EMAIL PROTECTED] wrote: Hey yall, I'm new to Python and I love it. Now I can get most of the topics covered with the Python tutorials I've read but the one thats just stumping me is Object Orientation. I can't get the grasp of it. Does anyone know of a good resource that could possibly put things in focus for me? Thanks. Learning Python (Lutz/Ascher) has a good discussion of the basics. Unfortunately, most of the OOP writings I've read fall into two catagories: Trivial examples where you say, But why Bother?? and examples that you don't understand until you've some OO design under your belt and can understand what it's all good for. Objects are, at the end of the day, data and the accompanying methods. Once you've read the various tutorials take a stab at converting a problem you know well into objects. You'll get it wrong at first. Most everyone does. Don't sweat it. Eventually, you'll just get it. -- http://mail.python.org/mailman/listinfo/python-list
Is there a better interactive plotter then pylab?
List: I'm trying to us pylab to see what I'm doing with some DSP algorithms, in case my posts about convolution and ffts weren't giving it away. I've been using pylab's plot function, but I'm finding it a bit cumbersome. It works, but if I switch from the interactive window to the plot window and back, the plot window gets trashed. Is there a better alternative for interactive use? Thanks Charles -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a better interactive plotter then pylab?
On Wed, 27 Apr 2005 20:56:07 -0500, John Hunter [EMAIL PROTECTED] wrote: Charles == Charles Krug [EMAIL PROTECTED] writes: Charles List: I'm trying to us pylab to see what I'm doing with Charles some DSP algorithms, in case my posts about convolution Charles and ffts weren't giving it away. Charles I've been using pylab's plot function, but I'm finding it Charles a bit cumbersome. Charles It works, but if I switch from the interactive window to Charles the plot window and back, the plot window gets trashed. Charles Is there a better alternative for interactive use? You are probably not using pylab interactive mode properly. matplotlib has several GUI backends (gtk, tk, qt, etc...). Most GUIs take control with their mainloop and prevent further interaction. From what you describe, I'm pretty sure you haven't setup your configuration properly for interactive use. Fortunately, there are a couple of solutions. For the standard python shell, you need to use the TkAgg backend. Tkinter is the only python GUI that plays nicely with the standard python shell. You will need to set backend : TkAgg and interactive : True in the matplotlib rc file. See http://matplotlib.sf.net/interactive.html for details and http://matplotlib.sf.net/.matplotlibrc for information on the configuration file. Those are already set. I'm taking a look at ipython now. -- http://mail.python.org/mailman/listinfo/python-list
Pythonic way to do static local variables?
I've a function that needs to maintain an ordered sequence between calls. In C or C++, I'd declare the pointer (or collection object) static at the function scope. What's the Pythonic way to do this? Is there a better solution than putting the sequence at module scope? Thanks. -- http://mail.python.org/mailman/listinfo/python-list
Re: Pythonic way to do static local variables?
On Mon, 25 Apr 2005 21:30:18 -0500, Jaime Wyant [EMAIL PROTECTED] wrote: Well, if you're a c++ programmer, Well, my forte is embedded systems and device controls . . . then you've probably ran into `functors' at one time or another. You can emulate it by making a python object that is `callable'. class functor: def __init__(self): self.ordered_sequence = [1, 2, 3, 4, 5] def __call__(self, arg1, arg2): self.ordered_sequence.extend((arg1,arg2)) self.ordered_sequence.sort() ordered in this case doesn't mean sorted. . . . 8-) It's the set of filter coefficients and cumulative remainders for an overlap add convolution. Sorting would be . . . bad. Like crossing the streams bad. Both of these techniques look promising here. Thanks -- http://mail.python.org/mailman/listinfo/python-list
Is there a package with convolution and related methods?
List: Is there a Python package with Convolution and related methods? I'm working on modeling some DSP processes in Python. I've rolled one up, but don't feel much like reinventing the wheel, especially if there's already something like Insanely Efficient FFT for Python already. Thanks Charles -- http://mail.python.org/mailman/listinfo/python-list
How can I verify that a passed argument is an interible collection?
List: I'm working on some methods that operate on (mathematical) vectors as in: def Convolution(x, y) Returns a list containing the convolution of vectors x and y Is there any way to determine at runtime that x and y are iterible collections? Do I *coughs* simply *coughs* trap the exception created by: for v in x: when v is a scaler quantity? Thanks Charles -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a package with convolution and related methods?
On Thu, 21 Apr 2005 13:13:17 -0400, David M. Cooke [EMAIL PROTECTED] wrote: Charles Krug [EMAIL PROTECTED] writes: List: Is there a Python package with Convolution and related methods? I'm working on modeling some DSP processes in Python. I've rolled one up, but don't feel much like reinventing the wheel, especially if there's already something like Insanely Efficient FFT for Python already. Thanks You most certainly want to look at the numerical python packages Numeric and numarray (http://numeric.scipy.org/) for array manipulations, and scipy (http://scipy.org) has wraps for FFTW (Fast Fourier Transform in the West). Great, thanks. Figured someone had done it. -- http://mail.python.org/mailman/listinfo/python-list
