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MathGroup Archive 2006

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Re: Count Function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg65520] Re: [mg65501] Count Function
  • From: Gregory Lypny <gregory.lypny at videotron.ca>
  • Date: Thu, 6 Apr 2006 06:52:02 -0400 (EDT)
  • References: <200604051055.GAA21742@smc.vnet.net> <55DC5ED6-AB89-4A5A-B93F-694BAD259CF6@yale.edu>
  • Sender: owner-wri-mathgroup at wolfram.com

Thanks János,

That would be my natural inclination: to combine two functions,  
Length and Select in this case, to get  a result that serves as a  
check of whatever I'm able to hammer out directly using something  
like Count.

	Regards,

		Gregory

On Wed, Apr 5, 2006, at 12:47 PM, János wrote:

>
> 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
>
>
> ----------------------------------------------
> Trying to argue with a politician is like lifting up the head of a  
> corpse.
> (S. Lem: His Master Voice)
>


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