Re: Sorting Rows of a Matrix

*To*: mathgroup at smc.vnet.net*Subject*: [mg65119] Re: Sorting Rows of a Matrix*From*: dh <dh at metrohm.ch>*Date*: Wed, 15 Mar 2006 06:28:35 -0500 (EST)*References*: <dv69a6$o6l$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hi Greg, you can solve thhis problem by using the second argument of Sort (see the manual). E.g. r will choose the sorting row: m={{1,3},{2,2},{3,1}}; r=1; Sort[m, #1[[r]] < #2[[r]] &] with r=2 we get: {{1, 3}, {2, 2}, {3, 1}} with r=2 we get: {{3, 1}, {2, 2}, {1, 3}} Daniel Gregory Lypny wrote: > Hello everyone, > > How can I sort the rows of a matrix by using one or more of the > columns as sort keys just like in a spreadsheet? For example, if > matrix M is 12 x 2 with numbers in the first column and unordered > month numbers in the second, how would I order the rows by month? > > Regards, > > Greg >