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Re: Average the same elements of the list

  • To: mathgroup at smc.vnet.net
  • Subject: [mg130896] Re: Average the same elements of the list
  • From: Daniel <dosadchy at its.jnj.com>
  • Date: Fri, 24 May 2013 06:23:17 -0400 (EDT)
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data={{{a1,b1,c1},d1},{{a2,b2,c2},d2}};
{#[[1, 1]], #[[All, 2]] // Mean} & /@ SplitBy[data, First]

output:
{{{a1, b1, c1}, d1}, {{a2, b2, c2}, d2}}

data={{{a1,b1,c1},d1},{{a1,b1,c1},d2}};
{#[[1, 1]], #[[All, 2]] // Mean} & /@ SplitBy[data, First]

output:
{{{a1, b1, c1}, (d1 + d2)/2}}

> Hello,
> I have list which is something like 
> data={
> {{a1,b1,c1},d1},{{a2,b2,c2},d2}}
> I would like to get new list which gets average of
> the second elements if the first elements in the
> sublists are all the same.
> Namely if a1=a2,b1=b2,c1=c2
> new list would look like
> datanew={{a1,b1,c1},Mean[{d1,d2}]
> Is there an elegant way to do this ?
> Thanks!
>



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