Forum Discussion

Anonymous's avatar
Anonymous
Not applicable
5 years ago
Solved

looping using DAX

Hello Everyone, I am very new with power BI and please I need help from expert. I need the DAX translation of this For Loop: a = 0; b = 0; for (int i=1; i<=n; i++) { a = x - b; b = x; } In ...
Need Help
  • parry2k's avatar
    parry2k
    5 years ago

    Anonymous this is a simple time intelligence calculation, and as a best practice, it is recommended to add a date dimension to your model to work with dates, and here is one of my post that talk about how to add a date dimension.

     

    Once it is done, just add the following measures, this can be done in one measure too, but I like to break these down for better understanding and also to reuse these measure (if required)

     

    Sum Current = SUM ( Table[Current] )

Sum Prev Day = CALCULATE ( [Sum Current], DATEADD ( 'Calendar'[Date], -1, DAY ) )

Increase = [Sum Current] - [Sum Prev Day]

     

    Check my latest blog post Year-2020, Pandemic, Power BI and Beyond to get a summary of my favourite Power BI feature releases in 2020

    I would ❤ Kudos if my solution helped. 👉 If you can spend time posting the question, you can also make efforts to give Kudos to whoever helped to solve your problem. It is a token of appreciation!

    ⚡Visit us at https://perytus.com, your one-stop-shop for Power BI-related projects/training/consultancy.⚡

parry2k's avatar
parry2k
Super User
5 years ago

Anonymous can you share the code you are using in the advanced editor?

Anonymous's avatar
Anonymous
Not applicable
5 years ago

I found something that could be easier if I understand how it works. this method is using calculated column and here is the code:

For Loop =
// Provide some starting values
VAR __n = 5
VAR __sum = 0
// Generate a "loop table", this will emulate a for loop for i=1 to some number
VAR __loopTable = GENERATESERIES(1,__n)
// Add in our calculated sum, emulating calculations done as iterations over the loop
VAR __loopTable1 = ADDCOLUMNS(__loopTable,"__sum",__sum + SUMX(FILTER(__loopTable,[Value]<=EARLIER([Value])),[Value]))
// Determine our MAX interation, the maximum value for "i"
VAR __max = MAXX(__loopTable1,[Value])
RETURN
// Return the value associated with the maximum value of "i" which is the last iteration in our "loop"
MAXX(FILTER(__loopTable1,[Value]=__max),[__sum])

My problem now is that I need to adapt this part: 
VAR __loopTable1 = ADDCOLUMNS(__loopTable,"__sum",__sum + SUMX(FILTER(__loopTable,[Value]<=EARLIER([Value])),[Value]))
so that it will do the calculation I want.

thanks