How to use fillmissing function within a group ?

I have a table where multiple columns have NaN and I want the NaN to be replaced by the previous valid value in the column, within the group(by ID.

T = 
    ID        amount1        amount2
    15        200                300
    15        NaN               800
    15        NaN               NaN
    67        NaN               300
    67        400                700
    67        NaN               NaN

Expected output:

    ID        amount1        amount2
    15        200                300
    15        200               800
    15        200               800
    67        NaN               300
    67        400                700
    67        400               700

I am able to achieve this partially using fillmissing function as:

Tupdated  = fillmissing(T,'previous');

But I want to implement this within group (by ID). I am unable to use fillmissing with splitapply correctly.

Answer 1

[dpb]

>> varfun(@(x) fillmissing(x,'previous'),T,'groupingvariables',{'ID'},'InputVariables',{'amount1','amount2'})
ans =
  6×4 table
    ID    GroupCount    Fun_amount1    Fun_amount2
    __    __________    ___________    ___________
    15        3             200            300    
    15        3             200            800    
    15        3             200            800    
    67        3             NaN            300    
    67        3             400            700    
    67        3             400            700    
>> 

[Namrata Goswami]

Thank you! This works for me.