Re: Partition a list based on columns

*To*: mathgroup at smc.vnet.net*Subject*: [mg119664] Re: Partition a list based on columns*From*: Ray Koopman <koopman at sfu.ca>*Date*: Thu, 16 Jun 2011 06:23:23 -0400 (EDT)*References*: <itcdai$d13$1@smc.vnet.net>

On Jun 16, 1:02 am, StatsMath <stats.ma... at gmail.com> wrote: > [...] > > What would be a good way to line up elements in a list in a diagonal > fashion, for ex: from Range[9] want to create the follwing matrix: > > 1 2 4 > 3 5 7 > 6 8 9 This will give a square matrix of order n whose elements are the integers 1...n^2 in the positions you asked for: m[n_] := With[{b=FoldList[Plus,0,Join[Range[n-1],Range[n-1,1,-1]]]}, Table[Take[b,{i,i+n-1}]+i,{i,n}]] m[5] {{ 1, 2, 4, 7, 11}, { 3, 5, 8, 12, 16}, { 6, 9, 13, 17, 20}, {10, 14, 18, 21, 23}, {15, 19, 22, 24, 25}}