Get leaves values

Source: R/mtg_getters_shortcuts.R

Get attribute values from the terminal nodes of the descendants sub-tree of a node (i.e. the "leaves" in computer science terms).

leaves(
  attribute,
  node = NULL,
  scale = NULL,
  symbol = NULL,
  link = NULL,
  filter_fun = NULL
)

Arguments

attribute

Any node attribute (as a character)
node

The MTG node
scale

An integer vector for filtering the .scale of the children (i.e. the SCALE column from the MTG classes).
symbol

A character vector for filtering the children by the name of their .symbol (i.e. the SYMBOL column from the MTG classes).
link

A character vector for filtering the .link with the children
filter_fun

Any filtering function taking a node as input.

Value

The attribute values from the children of the node

Note

This function is mainly intended to be used with mutate_mtg(). In this case, the node argument can be left empty (or you can put node = node equivalently).

Examples

filepath= system.file("extdata", "simple_plant.mtg", package = "XploRer")
MTG = read_mtg(filepath)

#> Warning: the condition has length > 1 and only the first element will be used
#> Warning: the condition has length > 1 and only the first element will be used
#> Warning: the condition has length > 1 and only the first element will be used
#> Warning: the condition has length > 1 and only the first element will be used

# The MTG has two leaves (node_5 and node_7):
leaves("Length", node = MTG)

#> node_5 node_7 
#>     10     12 
# We can check the function worked well by printing the symbols of each nodes:
print(MTG, ".symbol")

#>                    levelName    .symbol
#> 1 node_1                          Scene
#> 2  °--node_2                 Individual
#> 3      °--node_3                   Axis
#> 4          °--node_4          Internode
#> 5              ¦--node_5           Leaf
#> 6              °--node_6      Internode
#> 7                  °--node_7       Leaf

# If we need the terminal Internodes:
leaves("Length", node = MTG, symbol = "Internode")

#> node_6 
#>      6 

# Or the leaves at a given scale:
print(MTG, ".scale")

#>                    levelName .scale
#> 1 node_1                         NA
#> 2  °--node_2                      1
#> 3      °--node_3                  2
#> 4          °--node_4              3
#> 5              ¦--node_5          3
#> 6              °--node_6          3
#> 7                  °--node_7      3
leaves("Length", node = MTG, scale = 2)

#> node_3 
#>     NA