Take a column data by it's name to calculate

[Anonymous]

Hello! I need to use measure that returns the column name from one take using selectedvalue, and use this columnname to get the column. Example:
Here is my first table: 

id	attribute
1	Purchase
1	Emotion
1	Likability
2	Purchase
2	Likability
2	Emotion

I will use attribute column as a filter, those 3 attributes are the column names of my second table:

id	Purchase	Likability	Emotion
1	0.342	0.835	0.756
2	0.432	0.657	0.235
3	0.754	0.654	0.765

I need to create a formula, to calculated the average of one specific column based on attribute column from the first table:
so I now use:
var filter_attribute = selectedvalue('1 table'[attribute])
var mean = calculate(average(  '2 table'[*filter_attribute*] ))
What do I need to put filter_attribute(column name) to DAX will consider it as the column named like this? Thanks in advance!

[Greg_Deckler · Accepted solution]

@Anonymous I would highly recommend that you unpivot those three columns in your 2nd table and then this problem becomes trivial. Alternatively you would have to do this:

var filter_attribute = selectedvalue('1 table'[attribute])

var mean = 
  SWITCH(__filter_attribute,
    "Purchase",calculate(average(  '2 table'[Purchase] )),
    "Likeability",calculate(average(  '2 table'[Likeability] )),
    "Emotion",calculate(average(  '2 table'[Emotion] )),
  )