Defined in tcl/ad-trees.tclDivides a list into groups.
The first element of the list provides the key value that starts a new group.
Example: tree_group {1 2 3 2 1 2 1 1 2 2} = {1 2 3 2} {1 2} 1 {1 2 2}
The optional argument node_level is a function that extracts the
value of an element. By default, this is the identity function id.
Example: tree_group {{a 1} {b 2} {c 1}} snd = {{a 1} {b 2}} {c 1}
- Parameters:
-
xs
node_level (defaults to "id"
)