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Re: Creating an ordered list of pairs

  • To: mathgroup at smc.vnet.net
  • Subject: [mg132083] Re: Creating an ordered list of pairs
  • From: Murray Eisenberg <murray at math.umass.edu>
  • Date: Mon, 2 Dec 2013 01:58:22 -0500 (EST)
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Table together with Flatten will do what you want:

     Flatten[Table[{i, 5 j}, {i, 1, 3}, {j, 1, 4}], 1]
= {{1,5},{1,10},{1,15},{1,20},{2,5},{2,10},{2,15},{2,20},{3,5},{3,10},{3,15},{3,20}}

An alternative to using indices with Table is to use Outer:

     Flatten[Outer[List, Range[3], 5 Range[3]], 1]
 {{1,5},{1,10},{1,15},{2,5},{2,10},{2,15},{3,5},{3,10},{3,15}}


On Dec 1, 2013, at 8:23 AM, amannucci <Anthony.J.Mannucci at jpl.nasa.gov> wrote:

> How do I create an ordered list of pairs of the following structure:
> {{x1,y1}, {x2,y2}, {x3,y3}, ...} ? I want x1, x2, and x3 to be increasing in constant-interval steps (e.g. 1,2,3) and similarly for the y's (e.g. 5,10,15). E.g.
> {{1,5}, {1,10}, {1,15}, {2, 5}, {2,10}, ...} etc.
>
> I cannot figure out how to do this with Table or Array. Is there another function that will do this?
>
> Table does not create the correct nesting or structure.

---
Murray Eisenberg                                    
murray at math.umass.edu
Mathematics & Statistics Dept.      
Lederle Graduate Research Tower           
University of Massachusetts 
710 North Pleasant Street  
Amherst, MA 01003-9305








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