Re: Python OOP Problem
Thanks for reply, but it doesn't fit to my task. If I will add later
other objects(and it will be very often) - I should stop the service,
but that would be very bad.
I think you meant if you add other classes.
I'm not sure, if this is solution, but test passed:
myimportmod = __import__('ClassName', globals(), locals(),
['ClassName'], -1)
mod = getattr(_myimportmod, 'ClassName')
o = mod();
o.myfunction();
The same way you can say: this won't work if you need to change your
'ClassName' class. That would require restart of your service. Then you
can use reload(). However, I do not see the big picture. What is your
program suppose to do?
L
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Re: Python OOP Problem
On Dec 29, 7:35 pm, Laszlo Nagy gand...@shopzeus.com wrote:
Thanks for reply, but it doesn't fit to my task. If I will add later
other objects(and it will be very often) - I should stop the service,
but that would be very bad.
I think you meant if you add other classes. I'm not sure, if this is
solution, but test passed:
myimportmod = __import__('ClassName', globals(), locals(),
['ClassName'], -1)
mod = getattr(_myimportmod, 'ClassName')
o = mod();
o.myfunction();
The same way you can say: this won't work if you need to change your
'ClassName' class. That would require restart of your service. Then you
can use reload(). However, I do not see the big picture. What is your
program suppose to do?
L
The program works under apache(mod_wsgi) and receives different
messages, depends upon the message it should give an answer. There are
a lot types of messages(something like service) - and if I change a
'ClassName' class(mostly I don't change - just throw away from db note
about it(if time of service ended))- other modules(for instance
ClassName2 ClassName3 etc.) work. And if I will edit the main class
(which loads them) all services may be down. That's why it is
important to make a generalized loader - which loads another class.
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Re: Python OOP Problem
On 12/29/2009 3:01 PM, Миклухо wrote:
On 28 дек, 18:29, Martin v. Loewismar...@v.loewis.de wrote:
In this case (you just started to learn Python), I recommend to take
an explicit approach. Create a dictionary that maps class names to
classes:
name2class = { MyObject : MyObject,
MyOtherObject : MyOtherObject,
Etc : Etc }
Then, when you receive the string class_name, you do
o = name2class[class_name]
o.myfunction()
HTH,
Martin
Thanks for reply, but it doesn't fit to my task. If I will add later
other objects(and it will be very often) - I should stop the service,
but that would be very bad.
you don't need to stop any service; just add into the dictionary:
name2class['NewObject'] = NewObject
I'm not sure, if this is solution, but test passed:
myimportmod = __import__('ClassName', globals(), locals(),
['ClassName'], -1)
mod = getattr(_myimportmod, 'ClassName')
o = mod();
o.myfunction();
--
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Python OOP Problem
Hi, all. My problem is: 1) I have a database(postgresql) 2)I'm getting some string from database(string is a classname - written by me). 3)I need to construct new object from this string. In java it's done by Class.forName().newInstance(); For instance: 1)I receive the string: MyObject. 2)o = MyObject(); 3)o.myfunction(); Saw this link http://stackoverflow.com/questions/452969/does-python-have-an-equivalent-to-java-class-forname, but it doesn't work for me. May be I do something wrong. I just started to learn python. Help, please. PS: Sorry for poor English. Mikluxo -- http://mail.python.org/mailman/listinfo/python-list
Re: Python OOP Problem
Hi, all. My problem is: 1) I have a database(postgresql) 2)I'm getting some string from database(string is a classname - written by me). 3)I need to construct new object from this string. In java it's done by Class.forName().newInstance(); For instance: 1)I receive the string: MyObject. 2)o = MyObject(); 3)o.myfunction(); Take a look at locals( ) and globals( ). The detailed answer depends on whether the class is defined in an imported module or is defined in the current namespace. From your example it seems the latter. Just in case it's the former, you could do this: import module_with_your_class astring = 'MyObject' o = getattr( module_with_your_class, astring ) If the class is defined in the module where you are, class MyObject: pass astring = 'MyObject' o = locals( )[astring]( ) If the class MyObject is not local, for example because you need 'o' in a function body, you can try globals( ) instead of locals( ). HTH, Daniel -- Psss, psss, put it down! - http://www.cafepress.com/putitdown -- http://mail.python.org/mailman/listinfo/python-list
Re: Python OOP Problem
Миклухо wrote:
Hi, all. My problem is:
1) I have a database(postgresql)
2)I'm getting some string from database(string is a classname -
written by me).
3)I need to construct new object from this string.
In java it's done by Class.forName().newInstance();
For instance:
1)I receive the string: MyObject.
2)o = MyObject();
3)o.myfunction();
Saw this link
http://stackoverflow.com/questions/452969/does-python-have-an-equivalent-to-java-class-forname,
but it doesn't work for me. May be I do something wrong. I just
started to learn python. Help, please.
In this case (you just started to learn Python), I recommend to take
an explicit approach. Create a dictionary that maps class names to
classes:
name2class = { MyObject : MyObject,
MyOtherObject : MyOtherObject,
Etc : Etc }
Then, when you receive the string class_name, you do
o = name2class[class_name]
o.myfunction()
HTH,
Martin
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Re: Python OOP Problem
On Dec 28, 7:29 am, Martin v. Loewis mar...@v.loewis.de wrote:
In this case (you just started to learn Python), I recommend to take
an explicit approach. Create a dictionary that maps class names to
classes:
name2class = { MyObject : MyObject,
MyOtherObject : MyOtherObject,
Etc : Etc }
Then, when you receive the string class_name, you do
o = name2class[class_name]
o.myfunction()
HTH,
Martin
The class needs to be instantiated, so the one line should be as
follows:
o = name2class[class_name]()
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Re: Python OOP Problem
name2class = { MyObject : MyObject,
MyOtherObject : MyOtherObject,
Etc : Etc }
Then, when you receive the string class_name, you do
o = name2class[class_name]
o.myfunction()
The class needs to be instantiated, so the one line should be as
follows:
o = name2class[class_name]()
Oops - thanks for pointing that out.
Martin
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Re: Python OOP Problem
On 28 дек, 18:02, Daniel Fetchinson fetchin...@googlemail.com wrote: Hi, all. My problem is: 1) I have a database(postgresql) 2)I'm getting some string from database(string is a classname - written by me). 3)I need to construct new object from this string. In java it's done by Class.forName().newInstance(); For instance: 1)I receive the string: MyObject. 2)o = MyObject(); 3)o.myfunction(); Take a look at locals( ) and globals( ). The detailed answer depends on whether the class is defined in an imported module or is defined in the current namespace. From your example it seems the latter. Just in case it's the former, you could do this: import module_with_your_class astring = 'MyObject' o = getattr( module_with_your_class, astring ) If the class is defined in the module where you are, class MyObject: pass astring = 'MyObject' o = locals( )[astring]( ) If the class MyObject is not local, for example because you need 'o' in a function body, you can try globals( ) instead of locals( ). HTH, Daniel -- Psss, psss, put it down! -http://www.cafepress.com/putitdown Thanks for your reply. It's really helpful. The hierarchy will be something like this(each file is a class): - RouterTable( where we take the string from db) Router.py(the class which instantiates MyObject) -- MyObject.py -- MyObject2.py -- MyObject3.py Because each class should work independently from other and I cannot stop my program when adding another Object. -- http://mail.python.org/mailman/listinfo/python-list
Re: Python OOP Problem
On 28 дек, 18:29, Martin v. Loewis mar...@v.loewis.de wrote:
Миклухо wrote:
Hi, all. My problem is:
1) I have a database(postgresql)
2)I'm getting some string from database(string is a classname -
written by me).
3)I need to construct new object from this string.
In java it's done by Class.forName().newInstance();
For instance:
1)I receive the string: MyObject.
2)o = MyObject();
3)o.myfunction();
Saw this
linkhttp://stackoverflow.com/questions/452969/does-python-have-an-equival...,
but it doesn't work for me. May be I do something wrong. I just
started to learn python. Help, please.
In this case (you just started to learn Python), I recommend to take
an explicit approach. Create a dictionary that maps class names to
classes:
name2class = { MyObject : MyObject,
MyOtherObject : MyOtherObject,
Etc : Etc }
Then, when you receive the string class_name, you do
o = name2class[class_name]
o.myfunction()
HTH,
Martin
Thanks for reply, but it doesn't fit to my task. If I will add later
other objects(and it will be very often) - I should stop the service,
but that would be very bad.
I'm not sure, if this is solution, but test passed:
myimportmod = __import__('ClassName', globals(), locals(),
['ClassName'], -1)
mod = getattr(_myimportmod, 'ClassName')
o = mod();
o.myfunction();
--
http://mail.python.org/mailman/listinfo/python-list
Re: Python OOP Problem
On 28 дек, 18:29, Martin v. Loewis mar...@v.loewis.de wrote:
Миклухо wrote:
Hi, all. My problem is:
1) I have a database(postgresql)
2)I'm getting some string from database(string is a classname -
written by me).
3)I need to construct new object from this string.
In java it's done by Class.forName().newInstance();
For instance:
1)I receive the string: MyObject.
2)o = MyObject();
3)o.myfunction();
Saw this
linkhttp://stackoverflow.com/questions/452969/does-python-have-an-equival...,
but it doesn't work for me. May be I do something wrong. I just
started to learn python. Help, please.
In this case (you just started to learn Python), I recommend to take
an explicit approach. Create a dictionary that maps class names to
classes:
name2class = { MyObject : MyObject,
MyOtherObject : MyOtherObject,
Etc : Etc }
Then, when you receive the string class_name, you do
o = name2class[class_name]
o.myfunction()
HTH,
Martin
Thanks for reply, but it doesn't fit to my task. If I will add later
other objects(and it will be very often) - I should stop the service,
but that would be very bad.
I'm not sure, if this is solution, but test passed:
myimportmod = __import__('ClassName', globals(), locals(),
['ClassName'], -1)
mod = getattr(_myimportmod, 'ClassName')
o = mod();
o.myfunction();
--
http://mail.python.org/mailman/listinfo/python-list
Re: Python OOP Problem
On 28 дек, 18:29, Martin v. Loewis mar...@v.loewis.de wrote:
Миклухо wrote:
Hi, all. My problem is:
1) I have a database(postgresql)
2)I'm getting some string from database(string is a classname -
written by me).
3)I need to construct new object from this string.
In java it's done by Class.forName().newInstance();
For instance:
1)I receive the string: MyObject.
2)o = MyObject();
3)o.myfunction();
Saw this
linkhttp://stackoverflow.com/questions/452969/does-python-have-an-equival...,
but it doesn't work for me. May be I do something wrong. I just
started to learn python. Help, please.
In this case (you just started to learn Python), I recommend to take
an explicit approach. Create a dictionary that maps class names to
classes:
name2class = { MyObject : MyObject,
MyOtherObject : MyOtherObject,
Etc : Etc }
Then, when you receive the string class_name, you do
o = name2class[class_name]
o.myfunction()
HTH,
Martin
Thanks for reply, but it doesn't fit to my task. If I will add later
other objects(and it will be very often) - I should stop the service,
but that would be very bad.
I'm not sure, if this is solution, but test passed:
myimportmod = __import__('ClassName', globals(), locals(),
['ClassName'], -1)
mod = getattr(_myimportmod, 'ClassName')
o = mod();
o.myfunction();
--
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