Re: Adding columns and rows to a table
- To: mathgroup at smc.vnet.net
- Subject: [mg33476] Re: Adding columns and rows to a table
- From: "Allan Hayes" <hay at haystack.demon.co.uk>
- Date: Fri, 22 Mar 2002 04:07:15 -0500 (EST)
- References: <a7crth$hug$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Philip,
Here I time a different way of doing what you want:
data= Table[Random[Integer,{0,9}],{500},{600}];
(a1=
data[[Join[#1,{-1,-1}]]][[All,Join[#2,{-1,-1}]]]&@@(Range/@
Dimensions[data])
);//Timing
{0.27 Second,Null}
Compare with your code
tab1=data;
(a2=
(tab1c = Transpose[
Append[Append[Transpose[tab1], Transpose[tab1][[-1]]],
Transpose[tab1][[-1]]]];
tab1d = Append[Append[tab1c, tab1c[[-1]]], tab1c[[-1]]] )
);//Timing
{3.13 Second,Null}
Check for correctness:
a1===a2
True
--
Allan
---------------------
Allan Hayes
Mathematica Training and Consulting
Leicester UK
www.haystack.demon.co.uk
hay at haystack.demon.co.uk
Voice: +44 (0)116 271 4198
Fax: +44 (0)870 164 0565
"Philip M. Howe" <pmhowe at lanl.gov> wrote in message
news:a7crth$hug$1 at smc.vnet.net...
> Hello,
>
> I want to add to a table two columns that match the last column, and
> two rows that match the last row.
>
> Thus, if my table is
>
> {{1,2,3,4},{5,6,7,8},{9,10,11,12}}; I want to modify it such that I
> end up with
>
> {{1,2,3,4,4,4}, {5,6,7,8,8,8}, {9,10,11,12,12,12}, {
> 9,10,11,12,12,12}, {9,10,11,12,12,12}};
>
> This works:
>
> tab1 = {{1, 2, 3, 4}, {5, 6, 7, 8}, {9, 10, 11, 12}};
>
> tab1c = Transpose[
> Append[Append[Transpose[tab1], Transpose[tab1][[-1]]],
> Transpose[tab1][[-1]]]];
> tab1d = Append[Append[tab1c, tab1c[[-1]]], tab1c[[-1]]] // TableForm
>
>
> However, I bet there are much more efficient and elegant ways of
> doing this. Any suggestions?
>
> Thanks in advance for the help. The ideas I obtain from you folks
> are extremely helpful.
>
> Regards,
>
> Phil
> --
> Philip M. Howe
> Program Manager, Stockpile Surety
> Los Alamos National Laboratory
>
> (505) 665-5332
> (505) 667-9498
> Fax: 505-665-5249
> email pmhowe at lanl.gov
> Mail Stop P945
>