Re: Find index of maximal element in multi-dimensional

*To*: mathgroup at smc.vnet.net*Subject*: [mg73544] Re: [mg73492] Find index of maximal element in multi-dimensional*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Wed, 21 Feb 2007 01:54:14 -0500 (EST)*Reply-to*: hanlonr at cox.net

z = Table[Random[], {5}, {6}] ; Last[Sort[Flatten[MapIndexed[{#2, #1} & , z, {2}], 1], OrderedQ[{#1[[2]], #2[[2]]}] & ]] {{4,6},0.94111} {Position[z,#][[1]],#}&[Max[z]] {{4,6},0.94111} Your approach does not work for arrays of higher dimension z = Table[Random[], {5}, {6},{4}] ; Last[Sort[Flatten[MapIndexed[{#2, #1} & , z, {2}], 1], OrderedQ[{#1[[2]], #2[[2]]}] & ]] {{5,5},{0.890354,0.0253132,0.877603,0.981199}} {Position[z,#][[1]],#}&[Max[z]] {{5,1,3},0.998183} Bob Hanlon ---- Andrew Moylan <andrew.j.moylan at gmail.com> wrote: > Hi all, > > Here's a two-dimensional array of numbers: > > z = Table[Random[], {5}, {6}] > > What's an efficient way of finding the index of the maximal element of > z? Here's one way: > > Last[Sort[Flatten[MapIndexed[{#2, #1} & , z, {2}], 1], > OrderedQ[{#1[[2]], #2[[2]]}] & ]] > > The output is like this: > > {{5, 4}, 0.921344} > > But it's so untidy. Any better ideas? > > Cheers, > > Andrew