rolling_count_where_time
rolling_count_where_time creates an update_by table operation that keeps a count of the number of values in a rolling window that pass a set of filters, using time as the windowing unit. Data is windowed by reverse and forward
time intervals relative to the current row.
Syntax
Parameters
| Parameter | Type | Description |
|---|---|---|
| ts_col | str | The name of the column containing timestamps. |
| col | str | The name of the column that will contain the count of values that pass the filters. |
| filters | Union[str, Filter, Sequence[str], Sequence[Filter]] | Formulas for filtering as a list of Strings. Any filter is permitted, as long as it is not refreshing and does not use row position/key variables or arrays. |
| rev_time | Union[int,str] | The look-behind window size. This can be expressed as an integer in nanoseconds or a string duration; e.g., |
| fwd_time | Union[int,str] | The look-forward window size. This can be expressed as an integer in nanoseconds or a string duration; e.g., |
Tip
Providing multiple filter strings in the filters parameter results in an AND operation being applied to the filters. For example,
"Number % 3 == 0", "Number % 5 == 0" returns the count of values where Number is evenly divisible by both 3 and 5. You can also write this as a single conditional filter ("Number % 3 == 0 && Number % 5 == 0") and receive the same result.
You can use the || operator to OR multiple filters. For example, Y == `M` || Y == `N` matches when Y equals M or N.
Returns
An UpdateByOperation to be used in an update_by table operation.
Examples
The following example performs an update_by on the source table using three rolling_count_where_time operations.
Each operation gives varying rev_time and fwd_time values to show how they affect the output. The windows for each operation are as follows:
op_before: The window starts five seconds before the current row, and ends one second before the current row.op_after: The window starts one second after the current row, and ends five seconds after the current row.op_middle: The window starts three seconds before the current row, and ends three seconds after the current row.
The following example performs an OR filter and computes the results for each value in the Letter column separately.
The following example uses a complex filter involving multiple columns, with the results bucketed by the Letter column.