Cleaning Data with FirstNonBlank

[ReadTheIron]

I have a table with some data missing.

Neighborhood	Street
East	Maple Rd
West	Pine Rd
East	Birch St
East	Maple Rd
	Maple Rd
West	Pine Rd
West	Oak St

I want to create a column that will fill in the blanks based on the complete entries. I'm pretty sure I can use FirstNonBlank to do this, but I can't figure out the expression to use. I tried FullNeighborhood = FIRSTNONBLANK(Table[Neighborhood], [Street]) but my table just looks like this:

Neighborhood	FullNeighborhood	Street
East	East	Maple Rd
West	West	Pine Rd
East	East	Birch St
East	East	Maple Rd
		Maple Rd
West	West	Pine Rd
West	West	Oak St

[v-yangliu-msft · Accepted solution]

Hi @ReadTheIron ,

According to your description, You want to create a column based on the [Street] field to complete the [Neighborhood] field. Right?

Here are the steps you can follow：

(1)This is my test data:

(2)We can create a calculated column : “FullNeighborhood”

FullNeighborhood =
var _street='Table'[Street]
var _fullnei=MAXX( FILTER('Table','Table'[Street]=_street), [Neighborhood])
return
    _fullnei

The other way is :

FullNeighborhood2 = var _cuurent_street='Table'[Street]
var _table=SELECTCOLUMNS( FILTER('Table','Table'[Street]=_cuurent_street) , "Neighborhood" ,[Neighborhood])
var _first_non=LASTNONBLANK(_table,[Neighborhood])
return
_first_non

(3)The result is as follows:

If this method can't meet your requirement, can you provide some special input and output examples? Or a sample pbix after removing sensitive data. We can better understand the problem and help you.

If you need pbix, please click here.

case_01_0831.pbix

Best Regards,

Liu Yang

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly

[ToddChitt]

You could do it in Power Query. Right click on the source table and select DUPLICATE. Take that one, filter out the NULLs, then apply a GROUP BY step, (GROUP BY the two columns in question) adding something like a COUNT ROWS aggretation.

You could also do it in DAX with a SUMMARIZE function:

My Definitive table = SUMMARIZE ( 'Source table name', <first group by column>, <second group by column>, <Aggregation Name 1>, <aggregation operation 1>)

SUMMARIZE function (DAX) - DAX | Microsoft Docs

[ToddChitt]

So you need a difinitive source of where each Street is located. Maple is East, Oak is West, etc. To get that, copy your table, filter the blanks, then do a GROUP BY. Hopefully you won't have on Street located in two neighborhoods. That becomes your definitive source. Join that back to the list on Street. 

[ReadTheIron]

Could you walk me through how that GROUP BY would work?

[ToddChitt]

Power Query FILL DOWN might help.

What are you expecting to be seen in that blank cell? "East" because that row is also "Maple Rd" and the one before it is "Maple Rd"?

[ReadTheIron]

Yes, I'm expecting to see "East", because the other instances of "Maple Rd" have "East" in the neighborhood field. I need something that isn't position-dependent, though, my data might also look like:

Neighborhood	Street
West	Oak St
	Maple Rd
East	Birch St
	Oak St
West	Pine Rd
East	Maple Rd

And I want to create a column like

Neighborhood	FullNeighborhood	Street
West	West	Oak St
	East	Maple Rd
East	East	Birch St
	West	Oak St
West	West	Pine Rd
East	East	Maple Rd