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Re: a tricky List manipulation problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg16297] Re: [mg16211] a tricky List manipulation problem
  • From: "Wolf, Hartmut" <hwolf at debis.com>
  • Date: Sun, 7 Mar 1999 01:05:32 -0500
  • Organization: debis Systemhaus
  • References: <199903050540.AAA13494@smc.vnet.net.>
  • Sender: owner-wri-mathgroup at wolfram.com

Lieber Adalbert,

I forget to remark, the procedure I proposed gives the _sorted_ output
{tag, x, y} or {tag, y, x}. If this is undesidered, and if you can
identify the components in the output, e.g. by data type, just arrange
the output. Otherwise tag the input:

l1= Select[{#, 1,  Random[]}& /@ Range[13], #[[3]] <0.8 &]

{{1,1,0.623947},{2,1,0.527556},{3,1,0.208989},{4,1,0.212777},{5,1,0.115255},

{6,1,0.38422},{7,1,0.0553336},{8,1,0.601217},{9,1,0.187998},{10,1,0.281941},
 {13,1,0.33703}}

l2= Select[{#, 2,  Random[]}& /@ Range[13], #[[3]] <0.8 &]

{{1,2,0.183391},{2,2,0.102568},{3,2,0.183143},{4,2,0.741642},{6,2,0.231522},

{7,2,0.446785},{8,2,0.433839},{10,2,0.234453},{11,2,0.502992},{13,2,0.45169}}

f[{s_, x_}, {t_,_, y_}] /; s===t := {s, x, y}
f[_,{s_,_, x_}] := {s, x}

FoldList[f, {}, Union[l1,l2]]

{{},{1,0.623947},{1,0.623947,0.183391},{2,0.527556},{2,0.527556,0.102568},
 {3,0.208989},{3,0.208989,0.183143},{4,0.212777},{4,0.212777,0.741642},
 {5,0.115255},{6,0.38422},{6,0.38422,0.231522},{7,0.0553336},
 {7,0.0553336,0.446785},{8,0.601217},{8,0.601217,0.433839},{9,0.187998},
 {10,0.281941},{10,0.281941,0.234453},{11,0.502992},{13,0.33703},
 {13,0.33703,0.45169}}

Select[%, Length[#]==3 &]

{{1,0.623947,0.183391},{2,0.527556,0.102568},{3,0.208989,0.183143},
 {4,0.212777,0.741642},{6,0.38422,0.231522},{7,0.0553336,0.446785},
 {8,0.601217,0.433839},{10,0.281941,0.234453},{13,0.33703,0.45169}}

your's Hartmut

Hartmut Wolf, debis Systemhaus, Darmstadt, Germany
==============[mailto:hwolf at debis.com]============



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