Re: Assigning to a sublist
- To: mathgroup at smc.vnet.net
- Subject: [mg35173] Re: Assigning to a sublist
- From: Peter Pein <petsie at arcor.de>
- Date: Fri, 28 Jun 2002 02:31:03 -0400 (EDT)
- Organization: Arcor
- References: <afe4lv$h2h$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi Bob,
I didn't participate in writing the Mathematica-kernel, but I think it has z[[3]] as a
temporary, unnamed reference, when trying z[[3]][[2]]=sth.
It works fine, if you type:
In[2]:=
zz[[3,2]] = Append[zz[[3,2]], {1, 1, 1, 1, 1}]
Out[2]=
{{2, 1}, {1, 1, 1, 1, 1}}
In[3]:=
zz
Out[3]=
{{2, {{1, 1}}}, {10, {{3, 1}}}, {5, {{2, 1}, {1, 1, 1, 1, 1}}}}
Peter
Bob Harris wrote:
> Howdy,
>
> I'm trying to assign a new value to an entry in a sublist (of another list),
> and I can't understand why it won't work.
>
> For example, I do the following:
>
> In[1]:= zz = {{2, {{1, 1}}}, {10, {{3, 1}}}, {5, {{2, 1}}}}
> Out[1]= {{2, {{1, 1}}}, {10, {{3, 1}}}, {5, {{2, 1}}}}
>
> In[2]:= zz[[3]][[2]]
> Out[2]= {{2, 1}}
>
> In[3]:= Append[zz[[3]][[2]], {1, 1, 1, 1, 1}]
> Out[3]= {{2, 1}, {1, 1, 1, 1, 1}}
>
> In[4]:= zz[[3]][[2]] = Append[zz[[3]][[2]], {1, 1, 1, 1, 1}]
> Set::"setps : zz[[3]] in assignment of part is not a symbol."
> Out[4]= {{2, 1}, {1, 1, 1, 1, 1}}
<snip>
>
> Thanks,
> Bob H
>
>