Look up a value of a cell in the same column and using it in a DAX formula

[RiskyBiscuts]

Good Day, I have been struggling with transforming an Excel workbook into Power BI Desktop. The custom column is "Pop. per Density", and its an animal "Population" divided by a denominator. That denominator is the Median of the "Pop. Density" if the animal in the row matches the the animals in the "Animal" column.

Excel Formula:

Pop. per Density = IFERROR([@Population]/MEDIAN(IF([Animal]=[@Animal],[Pop. Density],"")),"")

I am still a novice with DAX, but in Excel the formula is straight forward. I just have no idea on how to reference a cell in a column, in PBI, and I cant seem to find a troubleshoot on that either.

Pop. per Density = IF( ISERROR( SEARCH("Cat", 'Animals'[Animal]) ), 0, CONVERT(MEDIAN( 'Animals'[Pop. Density]), INTEGER))

I just want to replace that string "Cat" with the value of the cell. Am I close? 

Animal	Population	Pop. Density	Pop. per Density
Cat	2.97
Fox	4.51	29.02	0.15
Eagle	2.11
Snake	1.34
Dog	5.62	18.64	0.39
Owl	0.11
Dog	1.28	4.54	0.09
Monkey	1.17
Dog	7.62	14.30	0.53
Frog	12.45

Any help on the above would be most appreciated!

[Fowmy · Accepted solution]

@RiskyBiscuts 

Can you see if the following calculated column solves your problem?

Pop. per Density = 

var __ani = Animal[Animal ] 
var __deno = 
    CALCULATE(
        MEDIAN( Animal[Pop. Density] ),
        Animal[Animal ] = __ani,
        REMOVEFILTERS(Animal)
    )
var __pop = Animal[Population ]
return
  DIVIDE( __pop , __deno )

[RiskyBiscuts]

Spot on! Yes this is what I meant to solve. Only thing I need to do is ignore the 0 and null values in the "Pop. per Density", as it turns I get a null value when 50% of the "Pop. Density" values are less then 0 or null. Do you know how I can ignore those 0 and null values? 

[Fowmy]

@RiskyBiscuts 

If you want to get rid of the blank and zero lines then you will have to create another with filter as follows:

New Animal = FILTER( Animal , Animal[Pop. per Density] <> BLANK() )

Or, you can create a measure as blanks are automatically hidden

Measure Pop. per Density = 

var __ani = SELECTEDVALUE(Animal[Animal ])
var __deno = 
    CALCULATE(
        MEDIAN( Animal[Pop. Density] ),
        Animal[Animal ] = __ani,
        REMOVEFILTERS(Animal)
    )
var __pop = SELECTEDVALUE(Animal[Population ])
return
DIVIDE( __pop , __deno )

[Greg_Deckler]

@RiskyBiscuts - I think what you want is:

Pop. per Density Column = 
  MEDIANX(FILTER('Animals',[Animal]=EARLIER('Animals'[Animal])),[Pop. Density])

Also, you can find a lot of Excel to DAX translations here: Excel to DAX Translation - Microsoft Power BI Community

[RiskyBiscuts]

Hey! Thanks for that link, its going to definately help me out!