Re: averaging sublists of different lengths

• To: mathgroup at smc.vnet.net
• Subject: [mg75509] Re: [mg75466] averaging sublists of different lengths
• From: bsyehuda at gmail.com
• Date: Thu, 3 May 2007 03:50:54 -0400 (EDT)
• References: <200705020747.DAA04729@smc.vnet.net>

```call your list l

then
With[{ml = Max[Length /@ l]},
Table[Mean[Flatten[Map[If[Length[#] >= i, #[[i]], {}] &, l]]], {i,
ml}]]

so for your data the result is
{686/11, 692/11, 710/11, 716/11, 714/11, 706/11, 328/5, 257/4,
456/7,
502/7, 212/3, 74, 250/3, 80, 74, 64, 88, 56}

regards
yehuda

On 5/2/07, dantimatter <dantimatter at gmail.com> wrote:
>
>
> Hello all,
>
> I have a list of lists like this:
>
> {{70, 66, 64, 68, 64, 56, 68, 78, 62, 68, 84}, {70, 64, 64, 56, 66,
> 56, 62,
>     64, 66, 88, 54, 72}, {58, 54, 54, 60, 72, 70, 62, 68, 74, 76, 70},
> {66,
>     56, 60, 64, 56, 62, 68, 58, 58, 58, 68, 76, 62, 76, 66, 64, 88,
> 56}, {56,
>     64, 72, 72, 70, 62, 76, 76, 76, 76, 86, 80, 100}, {60, 60, 70, 68,
> 60, 60,
>      50, 56, 60, 70, 62, 68, 88, 84, 82}, {54, 66, 72, 62, 70, 66,
> 70,
>     56}, {60, 60, 60, 62, 74, 80, 70}, {54, 62, 64, 72, 76, 74}, {66,
> 74, 70,
>     80, 54, 54, 64}, {72, 66, 60, 52, 52, 66, 66, 58, 60, 66}}
>
> What I'd really like is the average all the 1st values, 2nd values,
> etc, but I'm having trouble figuring out how to deal with the fact
> that the lists are not all the same length.   Is there a way to drop
> the sublists as they run out of points to add to the average, i.e. if
> I want the average of all the nth values, but Length[shortSublist] <
> n, can I somehow drop shortSublist and then calculate the average from
> the other sublists?
>
> Also, the Mean[] function requires more than one data point, but I'd
> still like to extract out the values for which there is only one data
> point.  Is there a way to do this?
>
> Thanks!
> dan
>
>
>

```

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