Re: the annoying, verbose self
braver wrote: Is there any trick to get rid of having to type the annoying, character-eating self. prefix everywhere in a class? Sometimes I avoid OO just not to deal with its verbosity. In fact, I try to use Ruby anywhere speed is not crucial especially for @ prefix is better- looking than self. But things grow -- is there any metaprogramming tricks or whatnot we can throw on the self? The most common answer you are going to get is that explicit is better than implicit, which I tend to agree with. Some people use 's' instead of 'self'. This shortens the number of characters you have to type, and is only one character more than the Ruby '@' prefix. Here is a metaprogramming technique that removes self, but I don't recommend these sorts of things, especially if other people are going to be looking at your code in the future. So use it at your own risk! http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/362305 -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Python strings question (vertical stack)
dmitrey wrote: Hi all, I have some strings, let it be string1, string2, string3. So how could String= string1 string2 string3 be obtained? Thank you in advance, D. If you just want the to add newlines between the strings then you can do the following: String = '\\n'.join([string1,string2,string3]) -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Python strings question (vertical stack)
J. Clifford Dyer wrote: I think you mean '\n'.join([string1,string2,string3]) You actually do want the \ to do its thing in this case. Yeah, my brain must still be asleep. Thanks for waking it up :) -- http://mail.python.org/mailman/listinfo/python-list
Re: simple? embedding question
[EMAIL PROTECTED] wrote: it works! could i cache maindict pointer in a global var or am i condemned to call PyObject* mainmod = PyImport_AddModule(__main__); assert(mainmod); PyObject* maindict = PyModule_GetDict(mainmod); assert(maindict); every time i want to PyRun_String? i call Py_Finalize only atexit. i also found boost library docs of some help: http://service-spi.web.cern.ch/service-spi/external/Boost/1.30.0/rh73_gcc32/libs/python/doc/tutorial/doc/using_the_interpreter.html btw what kind of object is returned in case i use Py_file_input in PyRun_String? Yes, you can keep a reference to maindict if you wish, but make sure you increment the reference count since PyModule_GetDict() returns a borrowed reference. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: simple? embedding question
[EMAIL PROTECTED] wrote: suppose i have imported two modules foo and bar with foo=PyImport_ImportModule(foo) and bar=PyImport_ImportModule(bar) respectively. Now suppose I have an artitrary python expression to evaluate. Do I need to parse that thring and check for foo. and bar. before jumping the usual PyModule_GetDict,PyDict_GetItemString,PyObject_CallObject hoop hoop on the PyObject for the prefix or there is a better way? btw PyRun_SimpleString(foo.baz()); does not work: Traceback (most recent call last): File string, line 1, in ? NameError: name 'foo' is not defined and i potentially need a PyObject* back with the result of the expression anyway. I believe the problem is that you are not importing the foo and bar modules into the __main__ scope. Try using PyImport_ImportModuleEx, which will allow you to specify the global scope to import the module into. For example, to import the modules into the __main__ scope you could do the following: PyObject* mainmod = PyImport_AddModule(__main__); PyObject* maindict = PyModule_GetDict(mainmod); foo = PyImport_ImportModuleEx(foo, maindict , maindict , NULL); bar = PyImport_ImportModuleEx(bar, maindict , maindict , NULL); Once the modules are imported into the __main__ scope, you should be able to use PyRun_SimpleString() to evaluate expressions. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: simple? embedding question
[EMAIL PROTECTED] wrote: i switched to PyImport_ImportModuleEx per your suggestion but i still get Traceback (most recent call last): File string, line 1, in ? NameError: name '__main__' is not defined i tried PyRun_SimpleString(__main__.foo.baz()); : Traceback (most recent call last): File string, line 1, in ? NameError: name '__main__' is not defined i do not have if __name__ == '__main__': statement anywhere in the module i'm importing, but nevertheless i checked that PyImport_AddModule(__main__); and subsequent getdict return non null pointers. does non null dictionary indicate that PyImport_AddModule succeeded as opposed to creating an empty module object? Sorry, I misunderstood the behavior of the PyImport_ImportModuleEx() function. You can use the PyImport_AddModule() function as before, but you must explicitly add the module to the __main__ module. Here is some code: PyObject *mainmod = PyImport_AddModule(__main__); PyObject *foo = PyImport_ImportModule(foo); Py_INCREF(foo); //Increment foo module since PyModule_AddObject() steals reference PyModule_AddObject(mainmod, foo, foo); PyRun_SimpleString(foo.baz()); -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: C API (embedded Python): How to get and set named variables
[EMAIL PROTECTED] wrote: From the C API (I'm using Python embedded), how can I get and set the value of named variables? Right now, I'm using hacks like PyRun_SimpleString(foobar = 12\n), but I'd really like to access the named objects directly. You can use the following C functions to set/get named attributes of an object: PyObject_SetAttrString PyObject_GetAttrString If the attributes belong to the global scope of a module, then you can use PyImport_AddModule to get a handle to the module object. For example, if you wanted to get the value of an integer in the __main__ module named foobar, you would do the following: PyObject *m = PyImport_AddModule(__main__); PyObject *v = PyObject_GetAttrString(m,foobar); int foobar = PyInt_AsLong(v); Py_DECREF(v); You will probably want to add some error checking in your code. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Subclassing zipfile (new style class)
Larry Bates wrote: import zipfile class walkZip(zipfile): pass if __name__ == __main__: print Hello World Traceback (most recent call last): File string, line 192, in run_nodebug File module1, line 2, in module TypeError: Error when calling the metaclass bases module.__init__() takes at most 2 arguments (3 given) In your code 'zipfile' is a module, not a class, so you cannot inherit from it. I believe this is what you are trying to accomplish: class walkZip(zipfile.ZipFile): pass -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about embedding python in C++
TheShadow wrote: When extending python in c/c++ after you register a module is there a way in c/c++ to check if they were correctly registered? Cause I'm having the problem where when I execute the the python script it finds the module but none of the functions. Are you calling Py_InitModule(...) in your initmodule function? If so, Py_InitModule(...) returns a reference to the module object. You can use this object to double check that your function names exist in the modules dictionary. Most likely, there is an error in your code. If you post it, it would be easier to tell what the problem is. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Catching SystemExit in C API code when embedding Python?
Stefan Bellon wrote:
Hi all!
I am embedding Python into a GUI application in a way that the GUI is
scriptable using Python.
Now I have come to a problem that when the user puts a sys.exit(0)
into his script to end the script, not only the script is terminated,
but also the GUI application itself. This is not the intended behaviour.
As in Python itself you can catch SystemExit, I think this should be
the way to go. But how do I catch this exception from within the C API?
Thanks in advance for any hints.
Have a look at the following doc page for handling exceptions with the C
api:
http://docs.python.org/api/exceptionHandling.html
Also, here is some sample code that will catch system exit exceptions:
//Call python code
...
//Check for system exit exception
if(PyErr_Occurred()) {
if(PyErr_ExceptionMatches(PyExc_SystemExit)) {
//handle system exit
PyErr_Clear();
} else {
PyErr_Print();
}
}
--
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Re: Catching SystemExit in C API code when embedding Python?
Stefan Bellon wrote: Thanks for your hints ... The interesting part is Call python code. In my example this is done with PyRun_SimpleString which does not return if an exception is not handled but raised out of the interpreter. So I am unsure of what you mean with Call python code. When installing an excepthook (see my other posting), then I can indeed catch all exceptions ... except for SystemExit which is the one I'm after. You cannot use PyRun_SimpleString, since it will automatically print and clear the error. You will need to use PyRun_String instead. -- http://mail.python.org/mailman/listinfo/python-list
Re: Another C API Question
beginner wrote: This works with PyFloat only. It does not work with integers. Did you try it out? I have used it on ints, bools, and objects that implement the __float__ method. It does not work on strings though. -- http://mail.python.org/mailman/listinfo/python-list
Re: Another C API Question
beginner wrote: I did and it did not seem to work. I ended up doing the following. Verbose, isn't it? If I do d=PyFloat_AsDouble(oDiscount); in the third if, I get an error. Maybe I missed something obvious. That's strange. I just tried the following code: fprintf(stdout,True = %lf\n,PyFloat_AsDouble(Py_True)); fprintf(stdout,False = %lf\n,PyFloat_AsDouble(Py_False)); fprintf(stdout,5 = %lf\n,PyFloat_AsDouble(PyInt_FromLong(5))); And it printed the following: True = 1.00 False = 0.00 5 = 5.00 What version of Python are you using? -- http://mail.python.org/mailman/listinfo/python-list
Re: Another C API Question
beginner wrote: I know obj is a number, but I do not know the exact type. How can I convert it to double without writing a giant switch() that exhausts every single type of number? Try using the PyFloat_AsDouble(...) function, it should be able to convert an object to a double, as long as the object implements the __float__ method. -- http://mail.python.org/mailman/listinfo/python-list
Re: pydoc with METH_VARGS
Stuart wrote: I'm asking if there's some sort of commenting or input file or something to customize the output pydoc generates. Thanks. AFAIK, there is no way to do this. However, you can edit the doc string for your function, which can include the argument list. I believe this is what most of Python's built-in functions do. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: EMBEDDING Run Python Run C Function
[EMAIL PROTECTED] wrote: At the moment i can run python-string-code from C (MinGW, WinXP) But how can i register a C-function in python-RUNTIME and call this C function from python - without wrapper dll's or libs??? Have a look at the following documentation page on extending/embedding python. I believe it does exactly what you want. http://www.python.org/doc/ext/extending-with-embedding.html -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: how to convert an integer to a float?
[EMAIL PROTECTED] wrote: Hi, I have the following functions, but ' dx = abs(i2 - i1)/min(i2, i1)' always return 0, can you please tell me how can i convert it from an integer to float? When two integers are involved in a division, the result will also be a division. If one of the operands is a float, then the result will be a float instead. So try casting one of the values to a float before performing the division: dx = float(abs(i2 - i1))/min(i2, i1) -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: how to convert an integer to a float?
Farshid Lashkari wrote: When two integers are involved in a division, the result will also be a division. My bad, I meant the result will also be an *integer* -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: f---ing typechecking
Szabolcs Nagy wrote: L=[1] L.extend((1,)) L [1, 1] Are list.extend() and list concatenation supposed to behave differently? I always thought concatenation was just shorthand for calling extend(). However the following seems to work: L = [1] L += (2,) L [1, 2] It seems like the '+' operator for lists should accept any iterable for the right side argument to be consistent with extend() and the '+=' operator. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: sending string or list to a function
manstey wrote: Is there a neat way to write a function that can receive either a string or a list of strings, and then if it receives a string it manipulates that, otherwise it manipulates each string in the list? The following code shows one way you can accomplish this. I don't consider it bad programming style to allow your functions to accept multiple data types. def MyFunction(val): if isinstance(val,basestring): val = [val] for s in val: #Process string -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Multithreaded C API Python questions
Svein Seldal wrote: I'm unable to get access to python as long as another python call is executing. The PyEval_AcquireThread() call blocks until the first call returns. I was hoping that the python system itself would release the GIL after some execution, but it itsnt. I am dependent upon the ability to have to threads executing in python land at the same time. How can this be done? Are you creating your threads through python or through C code? If you are only creating it through C code, then make sure you initialize the GIL with the following call at the beginning of your application: PyEval_InitThreads() From my experience, calling PyGILState_Ensure() was enough. I didn't need to call any extra threading functions. But make sure that every call to PyGILState_Ensure() is matched with a call to PyGILState_Release() -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: is this the right way to do subclasses?
John Salerno wrote: Ok, back to my so-called game. I'm just curious if I've implemented the subclasses properly, because it seems like an awful lot of repetition with the parameters. And again, if I want to add a new attribute later, I'd have to change a lot of things. I can't help but get the feeling that I'm doing something very inefficiently. Just accept variable arguments in the constructor of the sub-classes and forward them to the base class. class Fighter(Character): def __init__(self, *args, **kw): Character.__init__(self, *args, **kw) self.health += 2 self.strength += 1 This way, if you add a new parameter to the base class, you won't need to update all the derived classes. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: C wrapper
Sheldon wrote: Can anyone give me some idea as to what this error means? ImportError: dynamic module does not define init function I am new at this and there is still a lot to learn. Any help is appreciated, Take a look at the documentation for creating extension modules, especially the following page: http://docs.python.org/ext/methodTable.html The initialization function must be named initname(), where name is the name of the module, and should be the only non-static item defined in the module file -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Hooking file open
Hi, My goal is to detect all (or most) file dependencies of a script (i.e. modules, dlls, data files). Currently, after a script is finished executing I use sys.modules to determine all module dependencies, and I use win32process.EnumProcessModules to determine DLL dependencies. This works reasonably well, however I would still like to detect dependencies from regular file open calls. I did a little test by modifying __builtins__.open to point to a custom function that forwards the call to the original open function and saves the filename to a list. It seemed to work for simple test cases. Here is the code: def open_hook(*args,**kwargs): r = open_real(*args,**kwargs) saveFileName(args[0]) return r open_real = __builtins__.open __builtins__.open = open_hook Is this a safe approach? Is there a more efficient way of doing this? I realize that some dependencies will still fall through my checks, especially file opens from C extensions, which is fine. I just want to be able to detect the most common use cases. Any other suggestions are appreciated. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Hooking file open
Dale Strickland-Clark wrote: You might consider trapping calls to file() too, which is an alias for open(). Thanks, I didn't know about that. Also, I think I'd do my logging before calling the real function. It depends how you want to deal with exceptions. I placed the logging after the call to the real function so that files that don't exist will not be logged. However, I'm already checking for file existence during the post process of the script running, so I guess it doesn't really make too much of a difference. Thanks for the help. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: What is the cleanest way to for a module to access objects from the script that imports it?
[EMAIL PROTECTED] wrote: Wouldn't importing and re-importing the same modules cause considerable resource bulk? Or does python cache that stuff? If a module is already imported, then the import statement just uses the cached module. However, you can force a full reload of the module using the following syntax: reload(mymodule) -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: cleaner way to write this?
John Salerno wrote: Hi guys. I'm looking for a nicer, more compact way of writing this code. It doesn't have to be anything fancy, just something without the duplication and preferably only one return statement. def create_db_name(self): dlg = wx.TextEntryDialog(self.frame, 'Enter a database name:', 'Create New Database') if dlg.ShowModal() == wx.ID_OK: db_name = dlg.GetValue() dlg.Destroy() return db_name else: dlg.Destroy() return One problem is that if Cancel is pressed, I can't return anything. Another problem is that the dialog must be destroyed, so that has to come before any return statements. Thanks. This should work: def create_db_name(self): dlg = wx.TextEntryDialog(self.frame, 'Enter a database name:', 'Create New Database') db_name = None if dlg.ShowModal() == wx.ID_OK: db_name = dlg.GetValue() dlg.Destroy() return db_name -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: cleaner way to write this?
Paul Rubin wrote: I like if dlg.ShowModal() == wx.ID_OK: db_name = dlg.GetValue() else: db_name = None dlg.Destroy() return db_name better than db_name = None if dlg.ShowModal() == wx.ID_OK: db_name = dlg.GetValue() dlg.Destroy() return db_name but I suppose it's a matter of preference. Yeah, I think the second way is usually used by people who are more accustomed to programming in C, since they need to initialize variables. Your way is probably more Pythonic though. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: return tuple from C to python (extending python)
Simon Forman wrote: I have not done a great deal of extension work with python, however, I do not believe you can simply cast an int (or pointer to int, which is what you say dat is declared as, unless my C is /really/ rusty) to PyObject*. I think you need to do something like Py_BuildValue(i, 123), but see http://docs.python.org/ext/buildValue.html for more info. Simon is correct. You need to create a python object from your unsigned int. Try the following instead: PyTuple_SET_ITEM(toRet, i, PyInt_FromLong(dat[i]) ); -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: storing variable names in a list before they are used?
Hi John John Salerno wrote: how would I go about putting these variable names in a list? I know I can't leave them as above, but if I put them in as a string, then how do I later transform them into an actual variable for assign, such as: first_name = widget.get_text() Is there some kind of idiom that does this sort of work? What scope do you want these variable names to show up in? For example, if you want them to be defined in the global scope then you can do the following: name = 'first_name' globals()[name] = widget.get_text() print first_name If you want these variables to be assigned to an object then you can use setattr(): name = 'first_name' setattr(obj,name,widget.get_text()) print obj.first_name Hope this helps -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Releasing GIL in unknown state
Hi, Is there a proper way for C code to ensure that the GIL is released? I know about PyGILState_Ensure and PyGILState_Release, but that is to ensure the GIL is acquired. I have some extension code that does heavy processing and I want to release the GIL, but the code can't be sure that the GIL is already acquired. All I can think of so far is the following: PyGILState_STATE state = PyGILState_Ensure(); Py_BEGIN_ALLOW_THREADS //do processing Py_END_ALLOW_THREADS PyGILState_Release(state) Is there a better way? -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Inheritting Built In Types
Digital Logic wrote: Am I checking for the slice object incorrectly? That's the only thing I can think of. Yes. The slice object is the i variable in your code, not the data variable. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: error handling
Chris wrote: But sometimes you can have too many of these statements in your program, and it starts to get tangled and nasty looking. Is there a way I can modify sys.error so that when the interpreter comes accross an IndexError it prints That number is way too big! before it exits? Hi, Try placing the try/except block around the main function of your program: if __name__ == '__main__': try: main() except IndexError: sys.exit(That number is way too big!) -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: error handling
Steven D'Aprano wrote:
That's broken.
Imagine that somewhere in main() the following is called:
D = {a: apple, b: bicycle, c: cat}
print D[aardvark]
Your code now prints That number is way too big!. That's not good.
try...except blocks should, as a general rule, cover only the smallest
amount of code that they need to.
Hi Steven,
Point taken and I think your solution better addresses the root of the
problem. However, the OP said he wanted to print out that error message
whenever the interpreter came across any IndexError. So I gave him what
he wanted. I guess he needs to be more careful what he wishes for ;)
-Farshid
--
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Re: loop until keypress (Windows XP)
placid wrote: is there a way to do this, wait for user input but dont block? Hi, The msvcrt module should do what you want. Here is a sample: import msvcrt chr = 0 while chr != 'q': keep printing text if msvcrt.kbhit(): chr = msvcrt.getch() Keep in mind that this will only work on windows. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Missing MSVCR71.dll
The windows distribution of python was compiled with Visual Studio 7.1, so you need the 7.1 runtime libraries on your computer to run python. I haven't tried compiling an app with VS2005, but I don't see why they would be incompatible. I've compiled a python app using VS 7.0 and it worked fine. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Newbie question: what's with self?
donkeyboy wrote: This is probably a really basic question, but anyway ... I'm new to both Python and OO programming. From looking at a number of code examples, the word self is used a lot when referring to classes. As such, what does self mean and/or do? I've read things that say it's a naming convention, but no-one has really spelt it out (in idiot form!) in a way I can understand. Any help you can provide would be great: at the moment, when code doesn't work as expected, I'm randomly sprinkling selfs in all over the place to see if that helps, but without much of an idea of what it really achieves. Thanks in advance!! Hi, Take a look at the following FAQ on the python homepage: http://www.python.org/infogami-faq/general/why-must-self-be-used-explicitly-in-method-definitions-and-calls/ -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: singleton decorator
Andre Meyer wrote: Am I missing something here? What is the preferred pythonic way of implementing singleton elegantly? The Open Issues section of that PEP says the following: It's exceedingly unlikely that class decorators will be in Python 2.4 So it might not be in the current version of python. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Calling python functions from C
[EMAIL PROTECTED] wrote: I want to call add from C. Could anybody please help me? Look at the Pure Embedding section of the python documentation. It contains an example program that does exactly what you want. Here is a link to the page: http://www.python.org/doc/ext/pure-embedding.html -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: can someone explain why ..
Schüle Daniel wrote: I don't understand what is the difference between commented lines 1 and 2 with 1 uncommented and 2 commented it works as expected with 1 commented and 2 uncommented the picture doesn't appear I'm not familiar with Tkinter, but it seems as thought with 2, the image variable is garbage collected after the constructor of Main is called. With 1, you save a reference to the image, so it does not get garbage collected. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: can someone explain why ..
Schüle Daniel wrote: thx for quick reply :) image is local variable of imageLabel I would expect that in case imageLabel lives, it should hold alife objects bound to its local variables I am just curious *why* reference to image is not hold by imageLabel which on his part is hold by frame1 .. which is hold by global root These are the only lines of code that reference imageLabel: imageLabel = Label(master = frame1, image = image) imageLabel.pack() Unless the constructor of Label adds a reference of itself to frame1, imageLabel will also become garbage collected at the end of the constructor. Are you sure this is the case? -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: python to c API, passing a tuple array
[EMAIL PROTECTED] wrote:
Hi,
I want to pass something like this to a C function via the Python C
API.
mytuple = ((string_one, 1.2, 1.3), (string_two, 1.4, 1.5), ..,
., )
This tuple is dynamic in size, it needs to be 3 X N dimensions. each
tuple in the
tuple array is of the form (string, float, float) as described above
so from python:
mytuple = ((string_one, 1.2, 1.3), (string_two, 1.4, 1.5))
api.myCFunction(mytuple)
The C api:
static PyObject *myCFunction(PyObject *self, PyObject *args)
{
if (!PyArg_ParseTuple(args, O, . ?) {
printf( error in PyArg_ParseTuple!\n);
return Py_None;
}
Thanks.
Just loop through each item in the arguments and parse the sub-tuple.
Here is some sample code that doesn't do any error checking:
static PyObject *myCFunction(PyObject *self, PyObject *args)
{
int numItems, i;
PyObject *tuple;
numItems = PyTuple_Size(args);
for(i = 0; i numItems; ++i)
{
tuple = PyTuple_GetItem(args,i);
if(!PyArg_ParseTuple(tuple,sff,...) {
//handle error
Py_RETURN_NONE;
}
}
}
Also, you need to INCREF Py_None before you return it. Or you can use
the macro used in the sample code above.
-Farshid
--
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Re: From Python to c++
Any suggestions are very welcome! Are you allowed to use any boost libraries? If so then boost::any would probably help. The boost::any object can contain any object type. So you could have a single container that looked like the following: std::map std::string, std::vectorboost::any result; Since you know the type, you would use boost::any_cast to convert it to that type. You can find information about it here: http://www.boost.org/doc/html/any.html -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Passing a method indirectly
You don't need to pass the object along with the method. The method is bound to the object. Simply call the method by itself: def ObjApply(method): method() class Test: def test1 (self): print Hello def test2 (self): ObjApply(self.test1) ta = Test () ta.test2 () If you wanted to pass an unbound method, then it would look like the following: def ObjApply(object,method): method(object) class Test: def test1 (self): print Hello def test2 (self): ObjApply(self,Test.test1) ta = Test () ta.test2 () -- http://mail.python.org/mailman/listinfo/python-list
Re: when do two names cease to refer to the same string object?
I asked a similar question a few weeks ago. I think the answers I got will also answer your question as well. Here's a link to the thread: http://groups.google.com/group/comp.lang.python/browse_thread/thread/2f6f1d399ba94a7b/f564a219ffe44149?lnk=strnum=1hl=en#f564a219ffe44149 -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: file.read problem
I am working on a script to get parts of raw data out of a file, and
the data I read has to be the data written in the file without CR or
LF.
So you just want to remove all the linefeeds? This should work then:
data = data.replace('\n','')
-Farshid
--
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Re: file.read problem
When I do this I get the first 634 bytes. I tried using the:
f = open('myfile,'rb')
option, but now there are a few 0x0D bytes extra in myfile. 0x0D =
Carriage return. How can I make a program that not puts in the 0x0D
bytes in windows.
Try opening the file in 'rbU' mode. This will use universal newline mode
and convert all carriage returns to line feeds.
-Farshid
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Re: Is empty string cached?
A few comments (which I hope are correct, but which I hope you will read then mostly ignore since you probably shouldn't be designing based on this stuff anyway): Thanks for the info Peter. My original question wasn't due to any observed performance problems. I was just being curious :) -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Is empty string cached?
When I pass an empty string to a function is a new string object created or does python use some global pre-created object? I know python does this with integer objects under a certain value. For instance, in the following code is a new string object created for each function call? func(0,'') func(1,'') func(2,'') func(3,'') I tried the following commands in the interactive shell: x = '' y = '' x is y True x = 'hello' y = 'hello' x is y True This leads me to believe that python does reuse existing strings, but once the variables are removed, does the item still exist in the cache? -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: How to import a module with spaces in the name
Gregory Piñero wrote:
Let's say I have a module named Excellent Module.py
ExcellentModule = __import__('Excellent Module')
-Farshid
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Re: Is empty string cached?
It takes far too little evidence to induce belief: a = hello b = h+ello a is b False c = hello b is a False I don't understand the point of your last expression. Were you intending this instead: c is a True However, the following commands add to my confusion: a = 'wtf?' b = 'wtf?' a is b False So how are string literals cached? Is there an explanation somewhere? Is it some freaky voodoo, and I should just assume that a string literal will always generate a new object? Thanks, Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Is empty string cached?
I really don't understand why it's so important: it's not a part of the language definition at all, and therefore whatever behavior you see is simply an artifact of the implementation you observe. I guess I should rephrase my question in the form of an example. Should I assume that a new string object is created in each iteration of the following loop? for x in xrange(100): func(x,'some string') Or would it be better to do the following? stringVal = 'some string' for x in xrange(100): func(x,stringVal) Or, like you stated, is it not important at all? Thanks, Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Is empty string cached?
It just boils down to either a LOAD_CONST vs. a LOAD_NAME - either way the string isn't duplicated. Great, that's exactly what I wanted to know. Thanks Steve! -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: python spawn new process, rout stdin/out
Sounds like the popen2 module should suffice. Take a look at the documentation for the module here: http://www.python.org/doc/lib/module-popen2.html -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: translating PHP to Python
Is there a simple way to get the current object's name? You would think __name__ would work, right? It doesn't. className = item.__class__.__name__ I'd like to avoid passing a reference to an object's parent in __init__, but is there a built in way in Python to say You, Parent Object, do ...stuff! Use the super() function to access an attribute of a parent clas class C(B): def meth(self, arg): super(C, self).meth(arg) -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Embedding Python into C/C++ applications
John Dean wrote: Hi Could somebody, please tell me where I can find information about embedding Python into a C/C++ application. The example in the docs is rather simple. I am looking for something a bit more complex and longer Are you looking for a specific kind of example? Here is a link to a two part tutorial on Code Project that might help you out: http://www.codeproject.com/cpp/embedpython_1.asp http://www.codeproject.com/cpp/embedpython_2.asp -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: would it be feasable to write python DJing software
Levi Campbell wrote: Hi, I'm thinking about writing a system for DJing in python, but I'm not sure if Python is fast enough to handle the realtime audio needed for DJing, could a guru shed some light on this subject and tell me if this is doable or if I'm out of my fscking mind? What do you mean by DJing? Queueing and playing audio files? If so, python should work fine. Check out the PyMedia library for playing/mixing audio with python. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: calling a class method in a python module
Can anybody tell me how to call f in my C code?
Assuming you already have a handle to an instance of MyClass this should
do the trick:
PyObject *func = PyObject_GetAttrString(MyClassInst,f);
if(func) {
PyObject *result = PyObject_CallObject(func,NULL);
if(result) {
//Do something with result
Py_DECREF(result);
}
Py_DECREF(func);
}
Have a look in the Python/C API Reference Manual for more information.
-Farshid
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Re: Having Trouble with Scoping Rules
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 -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: A class with eventhandlers ?
It's definitely possible, here's a small example. There are probably
better ways to do it, but I'll let you figure that out ;)
class ErrorHandler:
def __init__(self,method):
self.method = method
self.errorHook = None
def onError(self,hook):
self.errorHook = hook
def __call__(self, *args, **kwargs):
if self.errorHook:
try:
self.method(*args,**kwargs)
except Exception, e:
self.errorHook(e)
else:
self.method(*args,**kwargs)
class MyClass:
def __init__(self):
self.load = ErrorHandler(self.load)
def load(self,filename):
return self.x
def IOErrorHook(e):
print 'Caught error:',e
c = MyClass()
c.load.onError(IOErrorHook)
c.load('filename')
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Re: exporting multiple modules from one dll?
I have a dll that contains all kinds of services (input, audio, video,
etc..), and I would like to export these to Python as separate modules.
Now, if I call Py_InitModule with a name that's different than the dll
name, I get an error. So what can I do?
I believe you can export different modules from one dll, but you *MUST*
at least export a module that has the same name as the dll. If the name
of your dll is mymodule.dll then your init function should look like the
following:
void initmymodule()
{
Py_InitModule(mymodule, mymoduleMethods);
Py_InitModule(audio, audioMethods);
Py_InitModule(video, videoMethods);
Py_InitModule(input, inputMethods);
}
At the python level you would have to do the following:
import mymodule #Must be import before audio,video, and input
import audio
import video
import input
I've never actually tried this, but I don't see why it wouldn't work.
Let me know how it goes.
-Farshid
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Re: generating method names 'dynamically'
Is it possible to have method names of a class generated somehow dynamically? If you don't know the name of the method ahead of time, how do you write the code for it? Do you use some dummy name? If so, once you have the name determined then you could use setattr to set the method name. Here's a simple example: class MyClass: def DummyMethodName(self): pass setattr(MyClass,'NewMethodName',MyClass.DummyMethodName) -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Executing script with embedded python
The problem is that PyObject_CallObject always returns NULL. Is this the correct return value for simply executing a script, as there is no function return value involved? The documentation for PyObject_CallObject states the following: Returns the result of the call on success, or NULL on failure. So it seems like the call is failing. My guess would be that modules are not callable objects. Also, this seems somewhat redundant since your module is effectively executed when you import it using the PyImport_Import function. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Problems with import of modules
How can I modify the python search-path from within the script, thus it
contains the doc directory?
Hi,
The sys.path variable is a list of strings that contains the current
module search path. You can add your own path to this list:
import sys
sys.path.append('../')
-Farshid
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Re: C Extended module init/cleanup
Can C extended python modules provide any kind module destructor, so
that whenever the module is unloaded some cleanup is run?
I've needed the same thing before but couldn't find it. AFAIK, the best
you can do is register an exit function that will be called when python
exits. Here is a sample code snippet:
//Called when python exits
void CleanupModule(void)
{
//Perform cleanup here
}
Then in your initmodule function add the following code:
//Register function to be called when python exits
Py_AtExit(CleanupModule);
-Farshid
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Re: Redirecting standard out in a single namespace
Fuzzyman wrote: Is there another way to shadow the sys module from a single namespace ? I've never actually tried this, but try making a copy of the sys module then replacing the stdout object with your own object. Then you can replace sys of the namespace with your custom sys module. I guess it would look something like this: import mysys #My dummy sys module import sys #Actual sys module #Copy sys module into dummy sys module mysys.__dict__.update(sys.__dict__) #Replace stdout with custom stdout mysys.stdout = MyStdout() #Replace sys of namespace namespace.sys = mysys This seems like it should work, however I don't know if copying the entire dictionary of one module to another is a safe thing to do. -Farshid -- http://mail.python.org/mailman/listinfo/python-list
Determine if object is a Bound or Unbound method
Hi, I have an object and I want to check if it is a bound or unbound method, or neither. I tried using the types module, but it seems as though types.UnboundMethodType and types.MethodType are equal. How else can I determine this? BTW, I'm using Python 2.3 Thanks, Farshid -- http://mail.python.org/mailman/listinfo/python-list
Re: Determine if object is a Bound or Unbound method
Grazie! Paolino wrote: Farshid Lashkari wrote: Hi, I have an object and I want to check if it is a bound or unbound method, or neither. I tried using the types module, but it seems as though types.UnboundMethodType and types.MethodType are equal. How else can I determine this? BTW, I'm using Python 2.3 Thanks, Farshid Bound methods has an im_self attribute set to the instance binding them Ciao ___ Yahoo! Messenger: chiamate gratuite in tutto il mondo http://it.beta.messenger.yahoo.com -- http://mail.python.org/mailman/listinfo/python-list
Re: How to find the classname of an object? (was Python Documentation)
This will get the name of an objects class
obj.__class__.__name__
This will return a tuple of its base classes
obj.__class__.__bases__
Christopher J. Bottaro wrote:
I actually want all the parent classes too. So if D derives off C derives
off B derives off A, I ultimately want a tuple ('D', 'C', 'B', 'A').
For those of you following the Python Documentation thread, this is a good
example of how the PHP manual is better. I found how to do this in a few
seconds in PHP. I searched the Python docs for class name, classname,
introspection and getclass. I looked in the Class section of the
tutorial also and also the Programming FAQ. The related functions
section of the PHP manual is really helpful. It would be cool if in the
section for the built-in function isinstance() or issubclass() there is a
section for related functions that would point me to getclassname(obj)
(if it exists).
Thanks for the help.
-- C
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