Re: Creating a list of 1x2 element arrays without procedural programming

*To*: mathgroup at smc.vnet.net*Subject*: [mg132084] Re: Creating a list of 1x2 element arrays without procedural programming*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Mon, 2 Dec 2013 01:58:42 -0500 (EST)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-outx@smc.vnet.net*Delivered-to*: mathgroup-newsendx@smc.vnet.net*References*: <20131201132345.2493B6A0D@smc.vnet.net>

This is essentially the same question you asked, with a simpler example, in an earlier post. And non-procedural solutions would be similar. Of course you may use Table, again with Flatten at level 1 to remove one level of nesting: Flatten[Table[{5 i, -10 j}, {i, 6, 9}, {j, 27, 24, -1}], 1] Alternatively, you may use Outer, again with Flatten: Flatten[Outer[List, 5 Range[6, 9], -10 Range[27, 24, -1]], 1] There are various alternatives to the 2nd and 3rd arguments of Outer there. E.g., Range[30, 45, 5] and Range[-270, -240, 10]. In fact, for a larger-scale problem the latter are doubtless more efficient than what I showed, which involved multiplication. Both solutions above give exact integers. You may then apply N to the entire result to get the approximate reals (with decimal points) that you requested. Flatten[Outer[List, 5 Range[6, 9], -10 Range[27, 24, -1]], 1] // N which uses a postfix notation that abbreviates: N[Flatten[Outer[List, 5 Range[6, 9], -10 Range[27, 24, -1]], 1]] Or you could use decimals in the ranges, e.g.: Flatten[Outer[List, Range[30., 45., 5], Range[-270., -240., 10]], 1] I suspect (but did not try it) that at least for a larger-scale problem of this sort, it's more efficient just to apply N at the end. On Dec 1, 2013, at 8:23 AM, amannucci <Anthony.J.Mannucci at jpl.nasa.gov> wrote: > Is there a way in Mathematica using built-in functions to create what the following procedural program does? > > latlong = {} > Do[AppendTo[latlong, {i, j}] , {i, 30.0, 45.0, > 5.0}, {j, -270.0, -240.0, 10.0}]; > latlong > > Out: > {{30., -270.}, {30., -260.}, {30., -250.}, {30., -240.}, {35., \ > -270.}, {35., -260.}, {35., -250.}, {35., -240.}, {40., -270.}, {40., \ > -260.}, {40., -250.}, {40., -240.}, {45., -270.}, {45., -260.}, {45., \ > -250.}, {45., -240.}} --- 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

**References**:**Creating a list of 1x2 element arrays without procedural programming***From:*amannucci <Anthony.J.Mannucci@jpl.nasa.gov>