Perform processing over each row of table starting from first non-zero element in that row

Hello is there a way to perform mean and movmean of each row of the table starting from its first non zero element?

Answer 1

[Matt J]

Your question implies that all elements of the table are numeric., e.g.,

T =

  5×3 table

     Var1       Var2       Var3  
    _______    _______    _______

          0          0    0.66783
    0.95769          0          0
          0          0          0
    0.67612    0.25479          0
          0          0    0.67533

If so, you may as well pre-convert it to a numeric array because...what is the benefit of holding it as a table anyway if they are all numbers?

 >> T=table2array(T)

T =

         0         0    0.6678
    0.9577         0         0
         0         0         0
    0.6761    0.2548         0
         0         0    0.6753

At this point, I would convert all initial zeros to NaN:

   [~,first]=max(logical(T));
   nanmap=(1:size(T,1)).'<first;
   T(nanmap)=nan;
   
   >> T

T =

       NaN       NaN    0.6678
    0.9577       NaN         0
         0       NaN         0
    0.6761    0.2548         0
         0         0    0.6753

and now you can simply use any of the column-wise mean functions with nanflag='omitnan'. For example,

>> result=movmean(T,3,1,'omitnan');
>> result(nanmap)=0

result =

         0         0    0.3339
    0.4788         0    0.2226
    0.5446         0         0
    0.2254    0.1274    0.2251
    0.3381    0.1274    0.3377       

[Matt J]

If you truly must have the result in table form, it is simple enough to convert it:

>> result=array2table(result,'VariableNames',{'Var1','Var2','Var3'})

result =

  5×3 table

     Var1       Var2       Var3  
    _______    _______    _______

    0.95769        NaN    0.33392
    0.47885        NaN    0.22261
    0.54461    0.25479          0
    0.22537     0.1274    0.22511
    0.33806     0.1274    0.33767