Hi!
I've got an class with a couple of depending methods.
I want to inheritance and create a new class where just
one method ist overwritten.
My problem: When python is executing the mother-method,
not the depending mother-method is taken, it take the
method of the chield.
In my example, i want that K2.bestCaptionl ong() returns
the same as KObject.bestCap tionlong() - no way!
I've tryed (in K2) something like:
def bestCaptionlong (self):
return KObject().bestC aptionlong()
which I expected to be like KObject::bestCa ptionlong() in
C++, but it doesn't work ;-(
Any Idea how to make the mother-class calling her method's?
Here is my Example:
class KObject:
def __init__(self):
self._label=Non e
self._caption=N one
self._captionlo ng=None
def __str__(self):
return (
"label: [%s], %s, (%s)\n"+
"caption: [%s], %s, (%s)\n"+
"captionlon g: [%s], %s, (%s)"
)%( self._label, self.label(), self.bestLabel( ),
self._caption, self.caption(), self.bestCaptio n(),
self._captionlo ng, self.captionlon g(), self.bestCaptio nlong()
)
def label(self):
return self._label
def caption(self):
return self._caption
def captionlong(sel f):
return self._captionlo ng
def bestLabel(self) :
return self.label()
def bestCaption(sel f):
if self.caption() is not None:
return self.caption()
else:
return self.bestLabel( )
def bestCaptionlong (self):
if self.captionlon g() is not None:
return self.captionlon g()
else:
return self.bestCaptio n()
class K2(KObject):
def bestCaption(sel f):
return "Overwritte n"
k = KObject()
k._label='x'
k2 = K2()
k2._label='x'
print k
print k2
Thanks, AXEL. 6 2211
Axel Straschil wrote: I've tryed (in K2) something like: def bestCaptionlong (self): return KObject().bestC aptionlong() which I expected to be like KObject::bestCa ptionlong() in C++, but it doesn't work ;-(
The following will do:
class Derived(Base):
def method(self):
return Base.method(sel f) # call base class method
(Of course you need not override the method if the body of the derived class
only calls the base class method.)
Peter
Hi! The following will do:
class Derived(Base): def method(self): return Base.method(sel f) # call base class method
I tried in my chield-class:
class K2(KObject):
def bestCaption(sel f):
return "Overwritte n"
def bestCaptionlong (self):
return KObject.bestCap tionlong(self)
The Problem ist inside of KObject.bestCap tionlong(self):
return self.bestCaptio n()
The mother-class is calling the method of the child-class, not
it own method. I want the mother-method to be called like "the
chield never was existing", but I find no way.
Anny other idea?
Thank, AXEL.
Axel Straschil wrote: Hi!
The following will do:
class Derived(Base): def method(self): return Base.method(sel f) # call base class method
I tried in my chield-class: class K2(KObject): def bestCaption(sel f): return "Overwritte n" def bestCaptionlong (self): return KObject.bestCap tionlong(self)
The Problem ist inside of KObject.bestCap tionlong(self): return self.bestCaptio n()
The mother-class is calling the method of the child-class, not it own method. I want the mother-method to be called like "the chield never was existing", but I find no way.
Anny other idea?
Thank, AXEL.
Change
return self.bestCaptio n()
to
return KObject.bestCap tion(self)
hth,
anton.
Axel Straschil wrote: Hi!
The following will do:
class Derived(Base): def method(self): return Base.method(sel f) # call base class method
I tried in my chield-class: class K2(KObject): def bestCaption(sel f): return "Overwritte n" def bestCaptionlong (self): return KObject.bestCap tionlong(self)
The Problem ist inside of KObject.bestCap tionlong(self): return self.bestCaptio n()
The mother-class is calling the method of the child-class, not it own method. I want the mother-method to be called like "the chield never was existing", but I find no way.
Anny other idea?
Thank, AXEL.
What you want seems to be
class KObject:
def bestCaptionlong (self):
# class made explicit to guard against overriding
return KObject.bestCap tion(self)
Some additional remarks:
Do-nothing accessor methods may be acceptable style in C++ but are
superfluous in Python.
The abundance of xxxCaption and label attributes somewhat obscures your
design goal for me, but usually the ability to override a method to change
its effect is a feature, not something to fight against.
Peter
Peter
[Axel] The mother-class is calling the method of the child-class, not it own method. I want the mother-method to be called like "the chield never was existing", but I find no way.
class A:
def bwahHaHa(self):
"""When called by callMe(), derived classes don't get a look in."""
print "Bwah-Ha-Ha!"
def callMe(self):
"""Calls non-overridable method bwahHaHa()."""
A.bwahHaHa(self ) ########## This is the interesting bit ##########
class B(A):
def bwahHaHa(self):
"""Vain attempt to override what callMe() does."""
print "Squeak"
b = B()
b.callMe() # Prints "Bwah-Ha-Ha!"
b.bwahHaHa() # Prints "Squeak"
--
Richie Hindle ri****@entrian. com
Hello! What you want seems to be class KObject: def bestCaptionlong (self): # class made explicit to guard against overriding return KObject.bestCap tion(self)
Yes, that behaves the way I excpected, thank's to you and the other
for helping me!
Do-nothing accessor methods may be acceptable style in C++ but are superfluous in Python.
I'm afraid I'm still not thinking in python, I'll work on it ;-)
Lg, AXEL. This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
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