15  The Pipeline Operator: %>>%

It is possible to create intricate Graphs with edges going all over the place (as long as no loops are introduced). Irrespective, there is usually a clear direction of flow between “layers” in the Graph. It is therefore convenient to build up a Graph from layers.

This can be done using the %>>% (“double-arrow”) operator. It takes either a PipeOp or a Graph on each of its sides and connects all of the outputs of its left-hand side to one of the inputs each of its right-hand side. The number of inputs therefore must match the number of outputs.


gr = po("scale") %>>% po("pca")
gr$plot(html = FALSE)