cumvarTopN
Syntax
cumvarTopN(X, S, top, [ascending=true], [tiesMethod=’latest’])
Please see Cumulative Moving TopN Functions (cumTopN functions) for the parameters and windowing logic.
Details
After stably sorting S in the specified ascending order, the function calculates the variance of the first top elements of X in a cumulative window.
Return value: DOUBLE type.
Examples
$ X=1 2 3 10 100 4 3
$ S = 0.3 0.5 0.1 0.1 0.5 0.2 0.4
$ cumvarTopN(X, S, 6, 4)
[,0.5,1,16.6666,1855.7,1546,1538.9666]
$ X = matrix(1..10, 11..20)
$ S = matrix(2022.01.01 2022.02.03 2022.01.23 NULL 2021.12.29 2022.01.20 2022.01.23 2022.01.22 2022.01.24 2022.01.24, NULL 2022.02.03 2022.01.23 2022.04.06 NULL 2022.02.03 2022.02.03 2022.02.05 2022.02.08 2022.02.03)
$ cumvarTopN(X, S, 6, 4)
#0 |
#1 |
|---|---|
0.5 |
|
1 |
0.5 |
1 |
1 |
2.9167 |
1 |
4.3 |
2.9167 |
5.6 |
4.3 |
6.8 |
5.6 |
6.8 |
7.7667 |
6.8 |
9.2 |
$ id=rand(10,10)
$ price=rand(100,10)
$ t=table(id, price)
$ select cumvarTopN(price, id, 6, 4) as result from t
result |
|---|
800 |
808.3333 |
730.25 |
825.2 |
903.3667 |
747.3667 |
856.7 |
887.4667 |
994.9667 |