List Length

1 Version

Takes a list-typed stream [t] and emits its element count as UInt64, exactly once per input tick. Element identity and content are discarded; only cardinality reaches the output.

How it fits

Typical backends

Per-tick crowd size derived from a detection list and shipped as JSON.

Empty-list branching: a list size feeds an expression gate that drives a downstream filter.

Throughput metric: list batches counted per tick and streamed live for charting.

Caveats

I/O contractEmits exactly one UInt64 per input list, so output cadence matches input cadence one-for-one.
I/O contractAn empty list emits 0 rather than nothing; downstream consumers must tolerate zero values when list contents are sparse.
Hard constraintThe element type t is unconstrained and never reaches the output; only the element count is reported and element identity and content are discarded.

Versions

342bebecdefaultlatestTransformation
10/12/2023