Find difference between numerical values in a Multivalue field

[jaysonpryde]

Hi,

As mentioned in the subject, I wanted to perform a simple subtraction operation on individual values/elements within a multivalue field.  So for example, I have a MV

23

79

45

23

38

I will iterate over the items, and perform the subtraction to get the following:

Iteration 1	diff = 0 (since it's the first element)
Iteration 2	diff = abs(79 - 23)
Iteration 3	diff = abs(45 - 79)
Iteration 4	diff = abs(23 - 45)
Iteration 5	diff = abs(38 - 23)

So far, here's what I did:

| makeresults
| eval a1="23,79,45,23,29"
| makemv delim="," a1
| mvexpand a1
| eval start=0
| eval i=0
| foreach a1
  [
    eval tmp='<<FIELD>>'
    | eval diff=if(start==0, 0, "subtract_element[i+1]_with_subtract_element[i]")
    | eval i=i+1
    | eval start=1
  ]

dummy query

I haven't implemented the subtraction logic yet, since obviously, I am having a challenging time in doing it. I've spent almost 3 hours already experimenting, but no luck.

Another weird thing (for me), which I can't explain, why the variable "i" is not incrementing even if I'm updating it within the foreach block.

Hope my question makes sense, and as usual, thank you very much in advance.

Any ideas are greatly appreciated

[kamlesh_vaghela · Accepted solution]

@jaysonpryde 

Is this you are looking for?

| makeresults
| eval a1="23,79,45,23,29"
| makemv delim="," a1
| mvexpand a1
| autoregress p=1 a1 | eval diff=abs(a1-a1_p1)

[jaysonpryde]

Hi @kamlesh_vaghela , Thank you very much for the reply.

And yes, that's what I am looking for. I just added a :

| fillnull value=0 diff

to set 0 for the first element.

Thanks again!