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

,"_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 — Manish Patel, Jun 04 '14 at 07:36

score 9 · Answer 1 · answered Jun 03 '14 at 20:09

9

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

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

answered Jun 03 '14 at 20:09

user1895961

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+ cast back to a symbol with `$ – Manish Patel Jun 04 '14 at 07:39
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@user2393012 I thought that, but in his example the new col is populated with strings. – user1895961 Jun 04 '14 at 14:45

score 1 · Answer 2 · edited Nov 28 '17 at 13:52

1

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"

edited Nov 28 '17 at 13:52

Thomas Smyth - Treliant

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answered Jun 04 '14 at 08:45

Rahul

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score 1 · Answer 3 · answered Aug 23 '16 at 10:22

1

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

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

answered Aug 23 '16 at 10:22

G. A.

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KDB concatenating strings inside select/exec statements

3 Answers3