kdb - How to use .year inside function in KDB?

Question

I would like to use dot notation to extract the year of a date.

q) myDate:2014.01.01;
q) myDate.year
2014i           / works OK

But when inside a function,

f:{[x] :x.year};
f[myDate]

I get an error (I use Studio for KDB+)

An error occurred during execution of the query.
The server sent the response:
x.year

What's going wrong?

Answer 1

根据code.kx 上的这个页面，这种行为是 q 的一个怪癖。为了解决这个问题，您可以使用 cast 功能。

q)f:{[x] :`year$x}
q)f[myDate]
2014i