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Dicken's avatar
Dicken
Post Prodigy
8 months ago
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List Generate Average as record;

  Hi, can someone explain what is happening here;   I have a standard accumulaton, with two outcomes  one for the sum and one for average ;  let alist = List.Numbers( 1, 20 ,1 ) in List.Genera...
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  • PhilipTreacy's avatar
    PhilipTreacy
    8 months ago

    Dicken 

     

    I'm not sure what you are asking here.

     

    Clearly in the code z and y are always the same.

     

    But what is this?  It makes no sense.  Where are you getting this from?

     

     z / 2   <>    z = y/2

     

    You can't say a thing (z/2) is not equal (or equal) to another thing (z=y/2). 

     

    You can't have an assignment on one side of a logical test like this

     

    Again not sure how esle to explain this other than how I have.

     

     z / 2   <>    z = y/2 makes no sense mathematically and I don't know what you are trying to do there.

     

    Phil

     

Dicken's avatar
Dicken
Post Prodigy
8 months ago

so let me see if i'm coming clsose becasue if i take 

= let alist = {1..10} in
List.Generate( ()=> [ x = 1 , y = alist {0} , z = alist {0} ] ,
each [x] <= List.Count( alist ) ,
each [ x = [x] + 1, y = [y] + alist {x-1} ,
z = ( [z] + alist {x-1} ) ] )

both x and y  = 6 at the third step, but if id divide  ( [z] + alist {x-1} )  / 2 = 2.25, , 
are you saying it is because it is part of an 'on going' accumulation and not an actual salcer value 
than can be divded ? 

jgeddes's avatar
jgeddes
Super User
8 months ago

You are correct. It is an ongoing accumulation. 
So when you write avg = ([avg] + alist{x-1})/x you would be storing the value you are calculating with that expression into the avg variable. That variable value is then used in the calculation in the next iteration in the list.