Fill in blank value with most resent value and reset at the new year.

[Anonymous]

I am looking to fill in blank values with the most recent values that resets to 0 after the new year. This worked last year because the data only had 2023 in it. Now the data goes until the end of 2024... You can see that in 2023 the YTD Count works correctly, taking the values found and missing in the Lookup row and filling them in. All looks well in this example because there just so happens to be a value for YearMonth 2024-1 in Lookup (2). In the case where that value is subsequently 0 my dilemna arises. it will pull the most recent value from 2023-9 of 15. I want that to reset at 2024-1 to be 0. 

The formula i have so far (works for a single year but doesnt work in the case of more than 1 year): 

YTD_Count =

IF('Whs Part Month'[Lookup] = BLANK(),

    VAR _whspart = 'Whs Part Month'[Whs and Part]

    VAR _date = 'Whs Part Month'[Date]

    VAR _filter = FILTER('Whs Part Month', 'Whs Part Month'[Whs and Part] = _whspart && 'Whs Part Month'[Date] <= _date && 'Whs Part Month'[Lookup] <> BLANK() )

    VAR _maxdate = MAXX(_filter, 'Whs Part Month'[Date])

    RETURN

    MAXX(FILTER(_filter, [Date] = _maxdate && [Whs and Part] = _whspart), [Lookup]), 'Whs Part Month'[Lookup])

I think the problem is the MAXX function not enabling the anual reset... help appreciated! 

[Fowmy · Accepted solution]

@Anonymous 

Use this calculated column:

YTD Count = 
  VAR _whspart = 'Whs Part Month'[Whs and Part]
  VAR _date = 'Whs Part Month'[Date]
  VAR _year = YEAR('Whs Part Month'[Date])
  VAR _T1 = 
      FILTER(
             'Whs Part Month',
             'Whs Part Month'[Whs and Part] = _whspart && 
             'Whs Part Month'[Date] <= _date &&
             'Whs Part Month'[Lookup] <> BLANK() &&
             YEAR( 'Whs Part Month'[Date] ) = _year

        )
  VAR _DateLast = MAXX( _T1 ,  'Whs Part Month'[Date] )
  VAR _result = MAXX(  FILTER( _T1  , 'Whs Part Month'[Date] =  _DateLast ) , 'Whs Part Month'[Lookup] )    
    RETURN
        COALESCE(_result,0)   

Scenario with no value to start 2024.