KDB concatenating strings inside select/exec statements

Question

I have a table T with column Sym:`IBM`MSFT`GOOG... Want the easiest way to create new column of the form newColumn: "IBM_Buy","MSFT_Buy","GOOG_Buy",...

The following does NOT seem to do the trick: select ((string Sym),"_Buy") from T

Eulogist

,"_Buy" doesn't work because you're working with a vector in the select statement, not an "atom" (although in this case we're working with strings which are not atoms either!). So user1895961 answer is the correct way – Renie

Answer 1

You need to use each-left (\:). Think of it as concatenating "_Buy" to each item on a list.

select (string[Sym],\:"_Buy") from T

Fuge

+ cast back to a symbol with `$ – Renie

@user2393012 I thought that, but in his example the new col is populated with strings. – Fuge

Answer 2

t:([]sym:`IBM`MSFT`GOOG)

update newsym:(string sym) cross enlist "_Buy" from t

or easy way (Dictionary Format)

t[`newsym] :
(string t[`sym]) cross enlist "_Buy"

Rely

Answer 3

You may use each-both (') function with anonymous function in select statement:

select {x, "_Buy"}'[Sym] from T

Polypary