[Tutor] Dynamically instantiating objects?
Israel Evans
israel@lith.com
Fri, 12 Apr 2002 08:26:51 -0700
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All this talk of constructors has got me thinking and confused... I would
think that constructors could help me out, but I can't seem to figure out
how.
I'm trying to instantiate a number of objects from a list.
Say for example I have three names in a list and I want an object created
that uses the names from that list as the name of that instance.
###
names = ['maude', 'claire', 'eudelle']
class pip:
def __init__(self, name, number):
self.name = name
self.number = number
for name in names:
name = pip(name, number)
###
The above just sets the variable "name" to be the instance of the pip class
three times over rather than setting up the current value of the variable as
the name of the instance.
###
class dynapip:
def __init__(self, name, number):
self.__name__ = name
self.number = number
for name in names:
dynapip(name, counter)
counter = counter + 1
###
This just seemed to create three instances of the class pip all with the
name __main__
I'm probably missing something fairly obvious, but since I'm obviously
missing something, I don't know what that something is now do I? hmmm... ;(
I've tried using eval to pass strings along, but that doesn't seem to work
either. Could one of you Grand Master Pythonistas perhaps clue me in here?
Thanks.
~Israel~
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<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;
font-family:Arial'><o:p> </o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>All this talk of constructors has got me =
thinking and
confused...<span style=3D'mso-spacerun:yes'> </span>I would think =
that
constructors could help me out, but I can't seem to figure out =
how.<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><o:p> </o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>I'm trying to instantiate a number of objects
from a list.<span style=3D'mso-spacerun:yes'> =
</span><o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>Say for example I have three names in a list =
and I
want an object created that uses the names from that list as the name =
of that
instance.<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>###<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>names =3D ['maude', 'claire', =
'eudelle']<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><o:p> </o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>class pip:<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><span =
style=3D'mso-tab-count:1'> &nbs=
p; </span>def
__init__(self, name, number):<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><span =
style=3D'mso-tab-count:2'> &nbs=
p; &nbs=
p; </span>self.name
=3D name<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><span =
style=3D'mso-tab-count:2'> &nbs=
p; &nbs=
p; </span>self.number
=3D number<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><o:p> </o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>for name in =
names:<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><span =
style=3D'mso-tab-count:1'> &nbs=
p; </span>name
=3D pip(name, number)<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>###<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>The above just sets the variable "name" to
be the instance of the pip class three times over rather than setting =
up the
current value of the variable as the name of the =
instance.<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><o:p> </o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><o:p> </o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>###<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>class dynapip:<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><span =
style=3D'mso-tab-count:1'> &nbs=
p; </span>def
__init__(self, name, number):<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><span =
style=3D'mso-tab-count:2'> &nbs=
p; &nbs=
p; </span>self.__name__
=3D name<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><span =
style=3D'mso-tab-count:2'> &nbs=
p; &nbs=
p; </span>self.number
=3D number<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><o:p> </o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>for name in =
names:<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><span =
style=3D'mso-tab-count:1'> &nbs=
p; </span>dynapip(name,
counter)<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><span =
style=3D'mso-tab-count:1'> &nbs=
p; </span>counter
=3D counter + 1<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><o:p> </o:p></span></font></p>
<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>###</span></font><font size=3D2 =
face=3DArial><span
style=3D'font-size:10.0pt;font-family:Arial;mso-fareast-font-family:"Tim=
es New Roman";
mso-fareast-language:EN-US'><o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>This just seemed to create three instances of =
the
class pip all with the name __main__<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><o:p> </o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>I'm probably missing something fairly obvious,
but since I'm obviously missing something, I don't know what that
something is now do I?<span style=3D'mso-spacerun:yes'> =
</span>hmmm...
;(<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>I've tried using eval to pass strings along, =
but
that doesn't seem to work either.<span =
style=3D'mso-spacerun:yes'>
</span>Could one of you Grand Master Pythonistas perhaps clue me in =
here?<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><o:p> </o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'>Thanks.<o:p></o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><o:p> </o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt;mso-no-proof:yes'><o:p> </o:p></span></font></p>
<p class=3DMsoAutoSig><font size=3D2 face=3D"Courier New"><span =
style=3D'font-size:
10.0pt;font-family:"Courier =
New";mso-no-proof:yes'>~</span></font><st1:country-region><st1:place><fo=
nt
size=3D2 face=3D"Courier New"><span =
style=3D'font-size:10.0pt;font-family:"Courier New";
=
mso-no-proof:yes'>Israel</span></font></st1:place></st1:country-region><=
font
size=3D2 face=3D"Courier New"><span =
style=3D'font-size:10.0pt;font-family:"Courier New";
mso-no-proof:yes'>~<o:p></o:p></span></font></p>
<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'><o:p> </o:p></span></font></p>
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