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MathGroup Archive 2006

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Re: Count Function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg65519] Re: [mg65501] Count Function
  • From: János <janos.lobb at yale.edu>
  • Date: Thu, 6 Apr 2006 06:52:01 -0400 (EDT)
  • References: <200604051055.GAA21742@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

On Apr 5, 2006, at 6:55 AM, Gregory Lypny wrote:

> The syntax will be the death of me.
>
> Count[X[[All,14]], -9.] will tally how many elements in column 14 of
> matrix X are equal to -9, but I can't for the life of me figure out
> how to get how many are greater than -9.  Any hint would be most
> appreciated.
>
> 	Greg
>

Here is a newbie approach:

In[1]:=
xmat = Table[Table[
     Random[Integer,
      {1, 100}], {i, 1, 20}],
    {j, 1, 30}]


In[6]:=
Length[Select[xmat[[All,14]],
    #1 > 9 & ]]
Out[6]=
25


János


----------------------------------------------
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corpse.
(S. Lem: His Master Voice)


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