473,578 Members | 3,150 Online
Bytes | Software Development & Data Engineering Community
+ Post

Home Posts Topics Members FAQ

enhancing/wrapping an existing instance of a duck

Basically I have an existing (maybe a rather large and complicated
(existing) instance) that
I want to add new member to.

Cheers
N

Hacks/attempts follow:

from math import sqrt

############ try2 ############
duck_obj = [ i*i for i in range(25) ] # OR a large sparse matrix

# I "want" to an a useful property, eg length, and retain the ducks
existing properties.
# I COULD try...
setattr(duck_ob j,"length",lamb da: sqrt(sum(*duck_ obj)))
print duck_obj.length () # returns 70
duck_obj[0]=70+71
print duck_obj.length () # returns 71

############ try2 ############
# **BUT** I'd rather encapsulate a the original instance somehow.

# I presume that I could define a class to do this somehow?
duck_obj = [ i*i for i in range(25) ] # OR a LargeSparseMatr ix()

dec = Vec(duck_obj) ???
print dec.length() # returns 70
duck_obj[0]=70+71 # original "large and complicated duck instance"
print dec.length() # returns 71

Any hints on how I need to define Vec so that any kind of duck_obj can
be decorated/wrapped/encapsulated.
Sep 1 '08 #1
0 769

This thread has been closed and replies have been disabled. Please start a new discussion.

Similar topics

10
3550
by: srijit | last post by:
Hello All, I have been seeing this term "duck typing" for quite sometime now. It will be nice if one of us can give an example in Python demonstrating duck typing and/or link to some Python references. Regards, Srijit
13
3837
by: Roy Smith | last post by:
I've got a C library with about 50 calls in it that I want to wrap in Python. I know I could use some tool like SWIG, but that will give me a too-literal translation; I want to make some modifications along the way to make the interface more Pythonic. For example, all of these functions return an error code (typically just errno passed...
5
5284
by: nimdez | last post by:
Hi, I am working on an existing code base in which a lot of data displayed to the user is formatted in tables. Most tables are printed row-by-row using printf() with "%s" print conversion specification for each column (e.g. printf(%10s %25s %15s\n", pszCol1, pszCol2, pszCol3)). My problem is that when a string is longer the column's width,...
2
1583
by: Andrzej Kaczmarczyk | last post by:
Hi I am experiencing something weird. maybe you could help me. I have two ineditable classes from outsource libraries: DataColumn and GridColumn I have built a wrapper class around DataColumn like this: public class MyDataColumn {
5
1193
by: Michael Dyremo | last post by:
Hello. We have a web-application built in ASP.NET using WebForms and Remoting. When selling this application we always incorporate it into the customers existing web-site. Our latest customer wishes to do some more advanced integration between our application and their existing site, namely using asp-includes to get the menusystem of...
1
1223
by: insyte | last post by:
I am writing a class that subclasses datetime.datetime in order to add a few specialized methods. So far the __init__ looks like this: class myDateTime(datetime.datetime): def __init__(self, time, *args, **kwargs): if isinstance(time, str): timeTuple, tzOffset = self.magicMethod(timeStr) datetime.__init__(self, tzinfo=GenericTZ(tzoffset),...
0
859
by: Paddy | last post by:
The official glossary entry here: http://docs.python.org/tut/node18.html#l2h-46 says: " duck-typing Pythonic programming style that determines an object's type by inspection of its method or attribute signature rather than by explicit relationship to some type object ("If it looks like a duck and quacks like a duck, it must be a duck.") By...
0
765
by: Neville Dempsey | last post by:
What do I need to add to HTMLDecorator? A simpler example: import cgi class ClassX(object): pass # ... with own __repr__ class ClassY(object):
16
3445
by: Joe Strout | last post by:
Let me preface this by saying that I think I "get" the concept of duck- typing. However, I still want to sprinkle my code with assertions that, for example, my parameters are what they're supposed to be -- too often I mistakenly pass in something I didn't intend, and when that happens, I want the code to fail as early as possible, so I have...
0
7778
by: Hystou | last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it. First, let's disable language...
0
8125
Oralloy
by: Oralloy | last post by:
Hello folks, I am unable to find appropriate documentation on the type promotion of bit-fields when using the generalised comparison operator "<=>". The problem is that using the GNU compilers, it seems that the internal comparison operator "<=>" tries to promote arguments from unsigned to signed. This is as boiled down as I can make it. ...
0
8290
jinu1996
by: jinu1996 | last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that...
1
7874
by: Hystou | last post by:
Overview: Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For...
0
8148
tracyyun
by: tracyyun | last post by:
Dear forum friends, With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the...
0
6522
agi2029
by: agi2029 | last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then...
0
5342
by: conductexam | last post by:
I have .net C# application in which I am extracting data from word file and save it in database particularly. To store word all data as it is I am converting the whole word file firstly in HTML and then checking html paragraph one by one. At the time of converting from word file to html my equations which are in the word document file was convert...
0
3781
by: TSSRALBI | last post by:
Hello I'm a network technician in training and I need your help. I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs. The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols. I succeeded, with both firewalls in...
0
3798
by: adsilva | last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?

By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use.

To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page.