CODEWITHSUNDEEP
kdb+q-lang
stretchr
stretchr

Reputation: 615

checking in list from kdb instance

I am storing strings in a list under variable name res. Next, I construct a query that will look into the list of strings. However it seems like the variable is not being read.

This is what I mean:

q) hdl: (to a port)
q) res: `string1`string2`string3
**q) ans: hdl"select count i by date,sym from trade where date=xxx, sym in `res"**

When I execute the command, I always get an empty result set. I know that the resultset cannot be empty. So how can I fix my query (in bold) to return results?

Please note I am performing the task from a q session in unix box.

Upvotes: 3

Views: 1966

Answers (2)

user1895961
user1895961

Reputation: 1186

Something like the following will work:

ans:hdl({select count i by date,sym from trade where date=xxx, sym in x};res)

@mollmerx is correct about having res defined locally and not on the remote process, although my query above is preferable to a functional select.

Upvotes: 6

mollmerx
mollmerx

Reputation: 648

You are setting res on the local process. You could fix this simply by doing:

hdl"res:`string1`string2`string3"

I think you will also need to remove the backtick from res in your select query.

Another suggestion is to not send a q string through the handle. You can continue to set res locally, but then do something similar to this:

hdl(?;`trade;((=;`date;xxx);(in;`sym;enlist res));0b;enlist[`cnt]!enlist(count;`i))

Upvotes: 2

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