Map Lambda

The map() Lambda maps each element of the timevector. This Lambda must return either a DOUBLE PRECISION, where only the values of each point in the timevector is altered, or a (TIMESTAMPTZ, DOUBLE PRECISION), where both the times and values are changed. An example of the map() Lambda with a DOUBLE PRECISION return:

SELECT (
   toolkit_experimental.timevector(time, value)
   -> toolkit_experimental.map($$ $value + 1 $$)
   -> toolkit_experimental.unnest()).*
FROM (VALUES (TimestampTZ '2021-01-06 UTC',   0.0 ),
             (            '2021-01-01 UTC',  25.0 ),
             (            '2021-01-02 UTC',   0.10),
             (            '2021-01-04 UTC', -10.0 ),
             (            '2021-01-05 UTC',   3.3 )
     ) as v(time, value);

The output for this example:

          time          | value
------------------------+-------
 2021-01-06 00:00:00+00 |     1
 2021-01-01 00:00:00+00 |    26
 2021-01-02 00:00:00+00 |   1.1
 2021-01-04 00:00:00+00 |    -9
 2021-01-05 00:00:00+00 |   4.3
(5 rows)

An example of the map() Lambda with a (TIMESTAMPTZ, DOUBLE PRECISION) return:

SELECT (
   toolkit_experimental.timevector(time, value)
   -> toolkit_experimental.map($$ ($time + '1day'i, $value * 2) $$)
   -> toolkit_experimental.unnest()).*
FROM (VALUES (TimestampTZ '2021-01-06 UTC',   0.0 ),
             (            '2021-01-01 UTC',  25.0 ),
             (            '2021-01-02 UTC',   0.10),
             (            '2021-01-04 UTC', -10.0 ),
             (            '2021-01-05 UTC',   3.3 )
     ) as v(time, value);

The output for this example:

          time          | value
------------------------+-------
 2021-01-07 00:00:00+00 |     0
 2021-01-02 00:00:00+00 |    50
 2021-01-03 00:00:00+00 |   0.2
 2021-01-05 00:00:00+00 |   -20
 2021-01-06 00:00:00+00 |   6.6
(5 rows)