topological.sort: Topological sorting of vertices in a graph
In igraph: Network Analysis and Visualization

topological.sort

R Documentation

Topological sorting of vertices in a graph

topological.sort() was renamed to topo_sort() to create a more consistent API.

topological.sort(graph, mode = c("out", "all", "in"))

`graph`	The input graph, should be directed
`mode`	Specifies how to use the direction of the edges. For “`out`”, the sorting order ensures that each node comes before all nodes to which it has edges, so nodes with no incoming edges go first. For “`⁠in⁠`”, it is quite the opposite: each node comes before all nodes from which it receives edges. Nodes with no outgoing edges go first.