Non hashable object (without __dict__)
Hello, I have a C++ application, I used SWIG to call the python code. I pass myModule.myObject object to the method of python code and what to store it in JSON format. The problem is when I do: o = myModule.myObject() inside python, the o object has __dict__ property, but if I take the passed object o like: def myMethod(self, objects): for o in objects: print o.__dict__ it fails saying no SwigPyObject does not have __dict__ property. The only way to use o properties is to call it by name like here: print o.MyProperty But in order to use json.dump( objects, file, default = self.MyJSONEncode ) I MUST to pass to MyJSONEncode method an object that has __dict__ as its property. So, what is the best way to correct my objects, which are coming from C ++ code to make them available for putting in JSON format ? Thank you. -- http://mail.python.org/mailman/listinfo/python-list
How to get python class serializable and well parsed by JSON
Hi people, I've created very nice post here: http://stackoverflow.com/questions/5274690/how-to-get-python-class-serializable-and-well-parsed-by-json-custom-encoder-deco Yes, there are solutions over the internet, but nothing works for my custom types. If you could answer, please read it. Be happy! Arthur -- http://mail.python.org/mailman/listinfo/python-list
Re: How to get python class serializable and well parsed by JSON
Common guys, help me, sweet heart to finish my job and go with my friend in the bar. Today we have a blues night :) Love it! Christina -- http://mail.python.org/mailman/listinfo/python-list
Re: How to get python class serializable and well parsed by JSON
Currently trying to pick up my ava http://en.gravatar.com/christinasanders21 for StackOverflow, which site I found very good for my questions, didn't I? Yes, and there are problem when adding a picture. Web admins should be careful. Can anyone explain me my problem ? : Christina -- http://mail.python.org/mailman/listinfo/python-list
c++ data types in python script
Hi people, I've used SWIG module to embed python inside c++ app. I pass a list of objects (with lots of different properties of types string, float, custom types like URL, Software and finally of list of strings). Now I'm in python. URL and Software has str() method that converts their value to string recognizable by JSON. But the problem is with list of strings. So, as I said I passed std::liststd::string myObjects to python function. Then I iterate it and for each object in myObjects I create a python copy (serialize it) to be able to put into JSON format and store in appropriate file. object has property benchmarks of type liststring. I do: ... class PythonObject: def __init__(self, object): self.benchmarks = list() for s in object.benchmarks: self.benchmarks.append(s) ... and it fails, also I do: ... class PythonObject: def __init__(self, object): self.benchmarks = [unicode(s) for s in object.benchmarks] ... and it fails, also I do: ... class PythonObject: def __init__(self, object): for s in object.benchmarks: print s[0] + s[1] + s[2] print type(s) ... and it fails printing wor type 'str' Segmentation fault (core dumped) $ also I do: ... class PythonObject: def __init__(self, object): self.benchmarks = unicode(object.benchmarks) ... and it does not fail, instead it puts in JSON this string: ... benchmarks: mymodule.StringList; proxy of Swig Object of type 'std::list std::string, std::allocator std::string *' at 0xb63ed4e8, ... but it is not what I need What I'm trying to stress is that c++ objects should be converted (serialized) before putting them into json. Otherwise type errors occur and process fails. I love learning python and hope somebody may suggest me or tell something. Thank you all anyway! Arthur -- http://mail.python.org/mailman/listinfo/python-list
Re: c++ data types in python script
Great! The solution is to use self.benchmarks = list(object.benchmarks). Now I'm battling with time_t type. C++ time_t converts to python int but it causes memore leaks due to destructor absence. I'm trying to figure it out. If anyone know, please share your thoughts. Be happy :) Arthur -- http://mail.python.org/mailman/listinfo/python-list
python data types in c++ code
Hi all, Ok, I managed to work with c++ data types in python and can store serialize c++ objects to store in json. Now the task is backward. I wrote a c++ code to get the list of objects using again python interface. The list of objects is returned. PyList. But I can't see how to convert PyObject as element of PyList to c++ data type or even how to convert or iterate PyList which is PyObject too. Please, whisper me the proper way I will go for. Be happy :) Arthur -- http://mail.python.org/mailman/listinfo/python-list
Re: python data types in c++ code
Ok people,
I do:
for (Py_ssize_t i = 0; i PyList_Size(py_list); ++i) {
PuObject* obj = PyList_GetItem(py_list, i);
if (obj != NULL) {
// howto get obj properties of different types
(map, list, string, int, bool) ?
}
}
Very clear code. The question is in the comment :)
Let's play more,
it's like jazz,
let's explore,
Baby baby baby bass
Keep yourselves,
Arthur
--
http://mail.python.org/mailman/listinfo/python-list
Re: python data types in c++ code
Stefan, great suggestion !! I will definitely bookmark this page and consider later. But my project dictate me use SWIG. I'm almost near the happy subend. Very curios on question I asked in previous message. Dear all, I love you too much :) Arthur -- http://mail.python.org/mailman/listinfo/python-list
Re: python data types in c++ code
Stephan, you are lead developer over there :))) It's marketing, however very nice solution.. I will propose my bosses to rediscover their world assumptions. You know, they are still using SVN, they are very loosely coupled to the past. I have to wash their brains... Meantime still battling with PyObject properties which are so diverse and disperse that I don't know... Keep talking guys Arthur -- http://mail.python.org/mailman/listinfo/python-list
Re: python data types in c++ code
In short, the answer is to use PyObject dictionary ? -- http://mail.python.org/mailman/listinfo/python-list
Re: python simplejson decoding
Good day people, So I have python file which can handle json data to put and get back it from a file say objects.json. Great. Now I want to run this code from within C++ application. I used swig to wrap the C++ class, which wants to call python code. It works fine, because when I import native python modules like simplejson or os.path the operation is successfull. But how to import my custom python code (not native builtin modules) ? There are following ways: - import as python module - call python file and its functions I prefer second way because I do not know how to define my custom module. If you know some examples, let me know please. Yes, I'm googling and reading off docs, but have not yet understood them. Arthur -- http://mail.python.org/mailman/listinfo/python-list
import python module from C++ code
Hi all, I have a C++ application. I have a .cpp file which is not a main program, but a class where I want to call python script (doSomething.py file). I'm using embed python like in a tutorial here: http://www.codeproject.com/KB/cpp/embedpython_1.aspx But the tutorial is bad. It does not explain howto create python module which they call in their example. doSomething.py file contains two classes, one of them I use externally (its functions). So I need to PyImport_Import(py_module) by name of this py file, but when I try to do that it fails. Please, give me some examples. If needed, I can attach my code as well. Thank you, waiting for anybody's response! Be happy. Arthur -- http://mail.python.org/mailman/listinfo/python-list
Re: import python module from C++ code
Yes, I did. Here the link http://docs.python.org/extending/extending.html#providing-a-c-api-for-an-extension-module It does not cover .py file embeding. So it is not my case. On Fri, Mar 4, 2011 at 7:03 PM, Santoso Wijaya santoso.wij...@gmail.comwrote: Have you read the doc [1] on extending/embedding Python? ~/santa [1] http://docs.python.org/extending/ On Fri, Mar 4, 2011 at 8:27 AM, Arthur Mc Coy 1984docmc...@gmail.comwrote: Hi all, I have a C++ application. I have a .cpp file which is not a main program, but a class where I want to call python script (doSomething.py file). I'm using embed python like in a tutorial here: http://www.codeproject.com/KB/cpp/embedpython_1.aspx But the tutorial is bad. It does not explain howto create python module which they call in their example. doSomething.py file contains two classes, one of them I use externally (its functions). So I need to PyImport_Import(py_module) by name of this py file, but when I try to do that it fails. Please, give me some examples. If needed, I can attach my code as well. Thank you, waiting for anybody's response! Be happy. Arthur -- http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
Re: import python module from C++ code
The problem is how to write python module under SWIG for C++ application Nor SWIG documentation neither embeding python documentation does not answer to this. If you can help, please, share your idea. Arthur -- http://mail.python.org/mailman/listinfo/python-list
Re: import python module from C++ code
Using simple words: I have mymodule.py file and c++ application. mymodule.py file contains two classes A and B. A class is a custom data type. B class contains functions putJSON, getJSON which I want to run from within C++ code. These functions are members of class B. So I need to import mymodule.py inside C++ app and call its members. Documentation does not explain this or it is written in a way that hard to catch out. I guess SWIG can help me to create a python module interface, but I can't do that since SWIG documentation is also poor in my case. Thank you for any help Arthur -- http://mail.python.org/mailman/listinfo/python-list
Re: import python module from C++ code
Still need the answer to the question: howto embed given python file (which contains python class and its members) into the c++ application ? I have to pass the arguments from c++ to python and back so I need to do conversions. They are ok. Fails PyImport_Import(my_module) call saying No module called mymodule. Then I need to create a mymodule based on given python file (its name mymodule.py). Can it be achieved using SWIG ? I'm very curious and looking for some feedback if possible :) Be happy. Arthur -- http://mail.python.org/mailman/listinfo/python-list
python simplejson decoding
Hi all, I'm trying an example (in attached file, I mean the bottom of this message). First, I create a list of 3 objects. Then I do: PutJSONObjects(objects) objects = GetJSONObjects() PutJSONObjects(objects, objects2.json) 1) PutJSONObjects(objects) method creates objects.json file (by default). It works fine. 2) Then objects = GetJSONObjects() method get the file contents and return. 3) Finally the script fails on the third method PutJSONObjects(objects, objects2.json) saying: AttributeError: 'dict' object has no attribute '__dict__' That is true, because objects returned by GetJSONObjects() is not a list of objects, but simple string So here is the question, please, how should I DECODE .json file into list of python objects so that I will be able to put the copy of these objects into a new file called objects2.json ? simplejson docs are hard to follow - without examples. Please, help me. Be happy! Arthur # Python-JSON method for caching my objects. import simplejson as json import os.path from datetime import datetime def GetJSONObjects(): # determine the json data file path filename = objects.json filepath = /home/docmccoy/Documents/ + filename if os.path.isfile(filepath): filename = filepath f = open(filename, 'r') objects = json.load( f ) print objects else: objects = list() return objects def PutJSONObjects(objects, filename = objects.json): # determine the json data file path filepath = /home/docmccoy/Documents/ + filename if os.path.isfile(filepath): filename = filepath f = open(filename, 'w') json.dump([o.__dict__ for o in objects], f, indent = 4 * ' ' ) class MyObject: def __init__(self, ID, url, category, osfamily, createDate): self.id = ID self.url = url self.category = category self.osfamily = osfamily self.createDate = createDate o1 = MyObject(1, http://google.com;, search, linux, unicode(datetime.now())) o2 = MyObject(2, http://localhost;, mycomp, None, unicode(datetime.now())) o3 = MyObject(3, http://milan.com;, football, windows, unicode(datetime.now())) objects = list() objects.append(o1) objects.append(o2) objects.append(o3) PutJSONObjects(objects) objects = GetJSONObjects() PutJSONObjects(objects, objects2.json) -- http://mail.python.org/mailman/listinfo/python-list
Re: arbitrary precision linear algebra
What do you mean by arbitrary precision ? Each method of calculating of something has its own precision... -- http://mail.python.org/mailman/listinfo/python-list
Re: arbitrary precision linear algebra
On Mar 2, 5:26 pm, Ben123 ben.is.loca...@gmail.com wrote: On Mar 2, 9:04 am, Arthur Mc Coy 1984docmc...@gmail.com wrote: What do you mean by arbitrary precision ? Each method of calculating of something has its own precision... If you are unfamiliar with arbitrary precision, I'm referring tohttp://en.wikipedia.org/wiki/Arbitrary-precision_arithmetic Suppose I find the eigenvalues of a matrix and the eigenvalues range from 1 to 0.0001. This can be handled by numpy in Python because the smallest eigenvalue is larger than then numerical precision of 1E-19. However, if the range of eigenvalues is 1 to 1E-40, then I will need to increase the precision of all calculations leading up to finding the eigenvalues. I am working with complex valued matrices and I expect to get real eigenvalues back (based on the physics of the system). The precision of numpy is apparent from the imaginary component of the eigenvalues I find, currently 1E-19 or 1E-20. I need better precision for small eigenvalues. In case you are curious, the complex-valued matrices are 20x20. Thanks You probably have to change the method of finding eigenvalues. Which one do you use? Power or algebraic ? Do you use Gaussian method to simplify matrices ? Languages can't support infinitely large or small numbers, so try to multiply the inner variables by 10^n to increase their values if this will not involve on the method. For example, I did this when was calculating geometric means of computer benchmarks. In such way you will be storing the number of zeros as n. Yes, interesting what are you calculating. -- http://mail.python.org/mailman/listinfo/python-list
Re: python simplejson decoding
Hi Peter, I implemented my decoder using your approach. Very positive. But that is for simple objects. My objects have nested lists. For example MyObject has property (member) called benchmarks, which is the list of defined benchmarks. I'm not sure if obj.__dict__.update will help me to copy nested information. I will see later. Now, when the testing environment is ready, I go for real world application. Thank you! Kostia On Mar 2, 4:24 pm, Peter Otten __pete...@web.de wrote: Arthur Mc Coy wrote: Hi all, I'm trying an example (in attached file, I mean the bottom of this message). First, I create a list of 3 objects. Then I do: PutJSONObjects(objects) objects = GetJSONObjects() PutJSONObjects(objects, objects2.json) 1) PutJSONObjects(objects) method creates objects.json file (by default). It works fine. 2) Then objects = GetJSONObjects() method get the file contents and return. 3) Finally the script fails on the third method PutJSONObjects(objects, objects2.json) saying: AttributeError: 'dict' object has no attribute '__dict__' That is true, because objects returned by GetJSONObjects() is not a list of objects, but simple string So here is the question, please, how should I DECODE .json file into list of python objects so that I will be able to put the copy of these objects into a new file called objects2.json ? simplejson docs are hard to follow - without examples. I suggest that you use json instead which is part of the standard library since Python 2.6. The documentation is here: http://docs.python.org/library/json.html If you know that there are only MyObject instances you need a function to construct such a MyObject instance from a dictionary. You can then recreate the objects with objects = [object_from_dict(d) for d in json.load(f)] or, if all dictionaries correspond to MyObject instances objects = json.load(f, object_hook=object_from_dict) A general implementation for old-style objects (objects that don't derive from object) is a bit messy: # idea copied from pickle.py class Empty: pass def object_from_dict(d): obj = Empty() obj.__class__ = MyObject obj.__dict__.update((str(k), v) for k, v in d.iteritems()) # * return obj If you are willing to make MyClass a newstyle class with class MyObject(object): # ... the function can be simplified to def object_from_dict(d): obj = object.__new__(MyObject) obj.__dict__.update((str(k), v) for k, v in d.iteritems()) # * return obj (*) I don't know if unicode attribute names can do any harm, obj.__dict__.update(d) might work as well. -- http://mail.python.org/mailman/listinfo/python-list
Re: arbitrary precision linear algebra
Are you saying python cares whether I express a number as 0.001 or scaled by 10^5 to read 100? If this is the case, I'm still stuck. I need the full range of eigenvalues from 1 to 1E-300, so the entire range could be scaled by 1E300 but I would still need better precision than 1E19 If python package can't compute 1E-300, then you can't use it. You can try to split your task onto small subtasks, which can be handled by specific python package. Then you need to think of the way to do that. Mathematically. If no way, then you can leave your task alone. Programming is limiting, that is true. I have heard about grid computing. You may find scientists working on grid and ask how do they split their tasks. But I think they do not an answer as well. Also google uses its matrix to rank web pages. It computes the maximum eigenvalue from the matrix which contain near zero entries too. Maybe you can find how do they store those values. Sorry, can't help anymore. I also have computing problems which I can't yet solve :) -- http://mail.python.org/mailman/listinfo/python-list
