kdb/q: apply the function, pass the return value to the function again, multiple rounds

Question

I have a list of symbols, say

 `A`B`C

. I have a table tab0; A function that takes in a table plus a string as arguments.

tab1: f[tab0;`A]
tab2: f[tab1;`B]
tab3: f[tab2;`C]

I only care about the final values. But my list of symbols can be long and can have variable length, so I don't want to hardcode above. How do I achieve it?

I think it has something to do with https://code.kx.com/q/ref/accumulators/ but I really struggle to figure out the syntax.

user_14254050 · Answer

This is exactly the use case for the binary application of over (/) (https://code.kx.com/q/ref/accumulators/#binary-application)

So you should use:

f/[tab0;`A`B`C]

kdb/q: apply the function, pass the return value to the function again, multiple rounds

1 Answers