# Updating input parameter over iteration
**URL:** https://forum.kx.com/t/updating-input-parameter-over-iteration/13407
**Category:** Community Support
**Tags:** kdb-and-q, imported
**Created:** [May 11, 2022, 12:00am UTC](https://forum.kx.com/t/updating-input-parameter-over-iteration/13407 "2022-05-11T00:00:00Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@mg4](https://forum.kx.com/u/mg4)
#### Post date: [May 11, 2022, 12:00am UTC](https://forum.kx.com/t/updating-input-parameter-over-iteration/13407/1 "2022-05-11T00:00:00Z")
[https://learninghub.kx.com/forums/topic/updating-input-parameter-over-iteration](https://learninghub.kx.com/forums/topic/updating-input-parameter-over-iteration)
Hi,
I was wondering if there’s a way to run a function over x number of iterations and also update a second value based on the function’s output.
For e.g.
summer:{[ID;y;z] y:y+z; ID:ID+1}
{summer[x;y;z]}[;2;2]/[{x\<750};0]
Currently this runs for 750 iterations however y and z are set to 2 on input so y always equals 4, I have checked this using namespaces.
Is there a way to include another over somewhere so that y will run like 2+2=4, 4+2=6… for 750 iterations?
Any help appreciated!!
PS. The code is being used within peach, that’s why I can’t just use namespaces or a global variable to upsert into.
---
### Author:  [@rocuinneagain](https://forum.kx.com/u/rocuinneagain)
#### Post date: [May 11, 2022, 12:00am UTC](https://forum.kx.com/t/updating-input-parameter-over-iteration/13407/2 "2022-05-11T00:00:00Z")
Something more like:
q)750{(x[0]+1;x[1]+x[2];x[2])}/0
0 2 750 1500 2
Or use a dictionary for readability:
q)750{x[`ID]+:1;x[`y]:sum x`y`z;x}/`ID`y`z!0 0 2
ID| 750
y | 1500
z | 2
---
### Author:  [@rocuinneagain](https://forum.kx.com/u/rocuinneagain)
#### Post date: [May 11, 2022, 12:00am UTC](https://forum.kx.com/t/updating-input-parameter-over-iteration/13407/3 "2022-05-11T00:00:00Z")
Is the `/` for of `do` what you are looking for?
[https://code.kx.com/q/ref/accumulators/#do](https://code.kx.com/q/ref/accumulators/#do")
```
q)750 +/2 2
754
```
---
### Author:  [@mg4](https://forum.kx.com/u/mg4)
#### Post date: [May 11, 2022, 12:00am UTC](https://forum.kx.com/t/updating-input-parameter-over-iteration/13407/4 "2022-05-11T00:00:00Z")
Hey, thanks for the reply.
So I think the above is quite close however it only allows you run sum, not appending to iteration id as required.
Following similar to above:
q)summer1:{[x;y] .m.x:x; x:x+y}
q)750 summer1[;2]/2;
q).m.x
1500
I’m probably missing something obvious but is there a way to manipulate this to append to ID per iteration so that:
q)summer:{[ID;y;z] y:y+z;.m.id:.m.id,ID;.m.y:y; ID:ID+1}
q).m.y
1500 (as above)
q).m.ID
750 (missing piece)
Thanks again!
---
### Author:  [@mg4](https://forum.kx.com/u/mg4)
#### Post date: [May 11, 2022, 12:00am UTC](https://forum.kx.com/t/updating-input-parameter-over-iteration/13407/5 "2022-05-11T00:00:00Z")
The very one.
Fair play and thanks!
---
### Author:  [@lkerr2](https://forum.kx.com/u/lkerr2)
#### Post date: [May 12, 2022, 12:00am UTC](https://forum.kx.com/t/updating-input-parameter-over-iteration/13407/6 "2022-05-12T00:00:00Z")
See article on the accumulator iteration operators:
[https://code.kx.com/q/ref/accumulators/](https://code.kx.com/q/ref/accumulators/")