Skip to main content

xT

Function xT 

Source
pub unsafe extern "C" fn xT(dictionary: K) -> K
Expand description

Constructor of q table object from q dictionary object.

ยงNote

Basically this is a flip command of q. Hence the value of the dictionary must have lists as its elements.

#[macro_use]
extern crate kdbplus;
use kdbplus::qtype;
use kdbplus::api::*;
use kdbplus::api::native::*;

#[no_mangle]
pub extern "C" fn create_table(_: K) -> K{
  let keys=unsafe{ktn(qtype::SYMBOL_LIST as I, 2)};
  let keys_slice=keys.as_mut_slice::<S>();
  keys_slice[0]=unsafe{ss(str_to_S!("time"))};
  keys_slice[1]=unsafe{ss(str_to_S!("temperature"))};
  let values=unsafe{knk(2)};
  let time=unsafe{ktn(qtype::TIMESTAMP_LIST as I, 3)};
  // 2003.10.10D02:24:19.167018272 2006.05.24D06:16:49.419710368 2008.08.12D23:12:24.018691392
  time.as_mut_slice::<J>().copy_from_slice(&[119067859167018272_i64, 201766609419710368, 271897944018691392]);
  let temperature=unsafe{ktn(qtype::FLOAT_LIST as I, 3)};
  temperature.as_mut_slice::<F>().copy_from_slice(&[22.1_f64, 24.7, 30.5]);
  values.as_mut_slice::<K>().copy_from_slice(&[time, temperature]);
  unsafe{xT(xD(keys, values))}
}
q)climate_change: libc_api_examples 2: (`create_table; 1);
q)climate_change[]
time                          temperature
-----------------------------------------
2003.10.10D02:24:19.167018272 22.1       
2006.05.24D06:16:49.419710368 24.7       
2008.08.12D23:12:24.018691392 30.5