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MathGroup Archive 2005

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Re: How to "search" in a matrix?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg60899] Re: [mg60892] How to "search" in a matrix?
  • From: ggroup at sarj.ca
  • Date: Mon, 3 Oct 2005 04:05:59 -0400 (EDT)
  • References: <200510020554.BAA01427@smc.vnet.net>
  • Reply-to: ggroup at sarj.ca
  • Sender: owner-wri-mathgroup at wolfram.com

On Sunday, October 2, 2005 at 01:54 GMT -0400, Renan wrote:

> I have this matrix:

> matr = {{a, b, 1}, {c, d, 2}, {e, f, 3}}

> I'm trying to do a "search" in a matrix. The "real" matrix will contain strings.
> How to "search" for a given value in a matrix and return all lines that have it?

> 'Select' seems to handle only lists - and this would require a
> Flatten, probably making my code too complicated and maybe slow (the
> real matrix will contain something like 100 elements - weather data).

I don't follow.  The following seems to work just fine:

In[1]:= matr = {{a, b, 1}, {c, d, 2}, {e, f, 3}, {a, b, 4}};
In[2]:= Select[matr, MemberQ[#,a]&]
Out[2]= {{a, b, 1}, {a, b, 4}}

As for string manipulation, look under Programming->String
Manipulation in the help browser.



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