Cross Transform

The cross transform compute the cross-product of a data stream with itself.

Transform Parameters

Property	Type	Description
filter	Expr	An optional filter expression for limiting the results of the cross-product.
as	Array	The output fields for the two data objects being crossed. The default is `["a", "b"]`.

Usage

If the input data is [{v:1}, {v:2}, {v:3}], then the transform definition

{"type": "cross"}

produces the output

[
  {"a": {"v": 1}, "b": {"v": 1}},
  {"a": {"v": 1}, "b": {"v": 2}},
  {"a": {"v": 1}, "b": {"v": 3}},
  {"a": {"v": 2}, "b": {"v": 1}},
  {"a": {"v": 2}, "b": {"v": 2}},
  {"a": {"v": 2}, "b": {"v": 3}},
  {"a": {"v": 3}, "b": {"v": 1}},
  {"a": {"v": 3}, "b": {"v": 2}},
  {"a": {"v": 3}, "b": {"v": 3}}
]

Similarly, with the same input data, the following transform

{"type": "cross", "filter": "datum.a !== datum.b"}

produces the output

[
  {"a": {"v": 1}, "b": {"v": 2}},
  {"a": {"v": 1}, "b": {"v": 3}},
  {"a": {"v": 2}, "b": {"v": 1}},
  {"a": {"v": 2}, "b": {"v": 3}},
  {"a": {"v": 3}, "b": {"v": 1}},
  {"a": {"v": 3}, "b": {"v": 2}}
]