Re: removing non-numeric elements from the table
- To: mathgroup at smc.vnet.net
- Subject: [mg108067] Re: removing non-numeric elements from the table
- From: David Reiss <dbreiss at gmail.com>
- Date: Sun, 7 Mar 2010 05:09:39 -0500 (EST)
- References: <hmqj5p$so5$1@smc.vnet.net>
Here is one approach:
Clear[Eq]
rnd := Random[];
Eq[] :=
Module[{soln},
soln = Flatten[{Solve[1/2 (Erf[z/Sqrt[2]] + 1) == 2 rnd - 1, z]}];
If[soln === {},
soln = {z -> Sequence[]}];
soln
];
tvR = Quiet[Table[z /. Eq[], {20}]]
--David
http://scientificarts.com/worklife
On Mar 5, 4:33 am, michael partensky <parten... at gmail.com> wrote:
> Hi. I am building a large table filled with the numerical solutions of an equation.
> Here is an example, where a normal standard variable is being generated.
>
> rnd:=Random[];
> Eq:=Solve[1/2 (Erf[z/Sqrt[2]]+1)==2 rnd-1,z];
> tvR=Quiet[Table[z/.Eq[[1]],{20}]];
>
> In[187]:=
> tvR
>
> Out[187]=
> {0.761439, z /. {}[[1]], z /. {}[[1]], 1.07111, 0.031784, z /. {}[[1]], z/.
> {}[[1]], 0.808313, -1.04238, z /. {}[[1]], 0.376982, z /. {}[[1]], 1.06622,
> z /. {}[[1]], -0.546643, -0.367224, 0.28111, -0.0606866, z /. {}[[1]], z/.
> {}[[1]]}
>
> What is a nicer way of removing the non-numeric elements? Clearly, it is
> possible to filter them out using say NumericQ, but I am looking for
> something more elegant (it is apart of a lecture), preferably right while
> the Table is being generated.
>
> Thanks
> Michael