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MathGroup Archive 2000

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Re: Getting coordinates of array member

  • To: mathgroup at smc.vnet.net
  • Subject: [mg26265] Re: [mg26247] Getting coordinates of array member
  • From: "Gareth J. Russell" <russell at cerc.columbia.edu>
  • Date: Sun, 10 Dec 2000 00:19:38 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

Stephane, you don't really need to define your own functions: Mathematica
has them already.

Note though, that it is conventional for matrix indices to indicate the row
first, and then the column, so your example is incorrect.

In[6]:=
data = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}

Out[6]=
{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}}

In[7]:=
data[[1, 3]]

Out[7]=
3

In[8]:=
Position[data, 7]
Out[8]=
{{3, 1}}

on 12/6/00 2:16 AM, Stephane Hebert at stephhebert at yourpants~videotron.ca
wrote:

> Ok, let's say I have this
> 
> 1  2  3
> -----------
> 1| 1  2  3
> 2| 4  5  6
> 3| 7  8  9
> 
> A 3x3 matrice or array.  Each number in the array represents its' position
> from top left to bottom right.
> 
> What I need to do is:
> 
> Find what position 1,3 is.  Just by looking at the array, we find that 7 is
> the answer.
> 
> Find what are the coordinates of 7.  Again just by looking at the array we
> see that the answer is 1,3
> 
> I need to come up with a simplu function that will return these.
> 
> pos = GetPos(x,y)
> 
> coord = GetCoord(pos)
> 
> I've done this before, way long ago and can't find it.

 
==================================================
Dr. Gareth J. Russell

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==================================================




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