Re: averaging sublists of different lengths

*To*: mathgroup at smc.vnet.net*Subject*: [mg75486] Re: averaging sublists of different lengths*From*: ap.alcover at gmail.com*Date*: Thu, 3 May 2007 03:38:38 -0400 (EDT)*References*: <f19fql$4q7$1@smc.vnet.net>

On 2 mai, 09:49, dantimatter <dantimat... 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 Good day, Here is my way to do it : In[1]:=data={{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}}; In[2]:=n=Max[Length/@data] Out[2]=18 In[3]:=data2=Transpose[PadRight[#,n,Null]&/@data]; In[4]:=data3=DeleteCases[#,Null]&/@data2 Out[4]={{70,70,58,66,56,60,54,60,54,66,72}, {66,64,54,56,64,60,66,60,62,74,66}, {64,64,54,60,72,70,72,60,64,70,60}, {68,56,60,64,72,68,62,62,72,80,52}, {64,66,72,56,70,60,70,74,76,54,52}, {56,56,70,62,62,60,66,80,74,54,66}, {68,62,62,68,76,50,70,70,64,66}, {78,64,68,58,76,56,56,58}, {62,66,74,58,76,60,60}, {68,88,76,58,76,70,66}, {84,54,70,68,86,62}, {72,76,80,68}, {62,100,88}, {76,84}, {66,82}, {64}, {88}, {56}} In[5]:=Mean/@data3//N Out[5]={62.3636,62.9091,64.5455,65.0909,64.9091, 64.1818,65.6,64.25,65.1429,71.7143, 70.6667,74.,83.3333,80.,74.,64.,88.,56.} V.Astanoff