[DB-SIG] Dictionaries Pass By Reference?
Duane and Karen
duaneh@connexus.net.au
Sat, 2 Nov 2002 17:01:57 +1100
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Sorry, I actually replied to the questioner's address, so I'm hoping I se=
nt
this to the right place. Following is a transcript of my earlier reply
(Sorry Tom.)
"
I actually bypassed that and passed a dictionary like so..
=A0
### code start ###
def get_new_dict_values(dict):
=A0=A0=A0 # change values
=A0=A0=A0 dict['key1'] =3D 'new value 1'
=A0=A0=A0 dict['key3'] =3D 'new key added'
=A0=A0=A0 return dict
=A0
def main():
=A0=A0=A0 # set up initial dicitonary
=A0=A0=A0 dict =3D {}
=A0=A0=A0 dict['key1'] =3D 'initial value 1'
=A0=A0=A0 dict['key2'] =3D 'initial value 2'
=A0=A0=A0 print dict
=A0=A0=A0 dict =3D get_new_dict_values(dict)
=A0=A0=A0 print dict
=A0=A0=A0 return
=A0
main()
### code end ###
=A0
The reason I would do this is because Python is a pure object oriented
language and as such it will reset the original dictionary object to the =
new
one, which is just a manipulated result of the one you passed. I cannot s=
ee
any ByReference (like VB) unless you make the dictionary global like the
following code, in which case you would not have to pass it... (Though th=
at
is just my opinion and I have yet to find the facts, but this seems logic=
al
for the language. :) )
=A0
### code start ###
=A0
def get_new_dict_values():
=A0=A0=A0 # change values
=A0=A0=A0 global dict
=A0=A0=A0 dict['key1'] =3D 'new value 1'
=A0=A0=A0 dict['key3'] =3D 'new key added'
=A0=A0=A0 return
=A0
def main():
=A0=A0=A0 # set up initial dicitonary
=A0=A0=A0 global dict
=A0=A0=A0 dict['key1'] =3D 'initial value 1'
=A0=A0=A0 dict['key2'] =3D 'initial value 2'
=A0=A0=A0 print dict
=A0=A0=A0 dict =3D get_new_dict_values()
=A0=A0=A0 print dict
=A0=A0=A0 return
=A0
### Set global dictionary
=A0
dict =3D {}
=A0
main()
=A0
### code end ###
=A0
Hope this helps,
=A0
Duane.
"
Duane Hennessy
Glen Iris, Victoria, Australia
=A0
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<DIV><FONT face=3DArial size=3D2><SPAN class=3D232345705-02112002>Sorry, =
I actually=20
replied to the questioner's address, so I'm hoping I sent this to the =
right=20
place. Following is a transcript of my earlier reply (Sorry=20
Tom.)</SPAN></FONT></DIV>
<DIV><FONT face=3DArial size=3D2><SPAN=20
class=3D232345705-02112002>"</SPAN></FONT></DIV>
<DIV><FONT face=3DArial size=3D2><SPAN class=3D232345705-02112002>I =
actually bypassed=20
that and passed a dictionary like so..</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><SPAN class=3D232345705-02112002>### =
code start=20
###<BR>def get_new_dict_values(dict):<BR> # change=20
values<BR> dict['key1'] =3D 'new value =
1'<BR> =20
dict['key3'] =3D 'new key added'<BR> return=20
dict</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><SPAN class=3D232345705-02112002>def=20
main():<BR> # set up initial =
dicitonary<BR> =20
dict =3D {}<BR> dict['key1'] =3D 'initial value=20
1'<BR> dict['key2'] =3D 'initial value =
2'<BR> =20
print dict<BR> dict =3D=20
get_new_dict_values(dict)<BR> print =
dict<BR> =20
return</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><SPAN =
class=3D232345705-02112002>main()<BR>### code=20
end ###</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><SPAN class=3D232345705-02112002>The =
reason I would=20
do this is because Python is a pure object oriented language and as such =
it will=20
reset the original dictionary object to the new one, which is just a =
manipulated=20
result of the one you passed. I cannot see any ByReference (like VB) =
unless you=20
make the dictionary global like the following code, in which case you =
would not=20
have to pass it... (Though that is just my opinion and I have yet to =
find the=20
facts, but this seems logical for the language. :) )</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><SPAN class=3D232345705-02112002>### =
code start=20
###</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><SPAN class=3D232345705-02112002>def=20
get_new_dict_values():<BR> # change=20
values<BR> global dict<BR> =
dict['key1'] =3D=20
'new value 1'<BR> dict['key3'] =3D 'new key=20
added'<BR> return</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><SPAN class=3D232345705-02112002>def=20
main():<BR> # set up initial =
dicitonary<BR> =20
global dict<BR> dict['key1'] =3D 'initial value=20
1'<BR> dict['key2'] =3D 'initial value =
2'<BR> =20
print dict<BR> dict =3D=20
get_new_dict_values()<BR> print =
dict<BR> =20
return</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><SPAN class=3D232345705-02112002>### =
Set global=20
dictionary</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><SPAN class=3D232345705-02112002>dict =
=3D=20
{}</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><SPAN=20
class=3D232345705-02112002>main()</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><SPAN class=3D232345705-02112002>### =
code end=20
###</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><SPAN class=3D232345705-02112002>Hope =
this=20
helps,</SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2><SPAN=20
class=3D232345705-02112002>Duane.</SPAN></FONT></DIV>
<DIV><FONT face=3DArial size=3D2><SPAN=20
class=3D232345705-02112002>"</SPAN></FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Duane Hennessy</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Glen Iris, Victoria, =
Australia</FONT></DIV>
<DIV> </DIV></BODY></HTML>
<BR>
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