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
>
>

• Prev by Date: Re: Difference /recurrence equations
• Next by Date: Re: Pretty output
• Previous by thread: Re: Assigning to a sublist
• Next by thread: Re: Assigning to a sublist