DiagrammeR (version 0.9.2)

rescale_edge_attrs: Rescale numeric edge attribute values

Description

From a graph object of class dgr_graph, take a set of numeric values for an edge attribute, rescale to a new numeric or color range, then write to the same edge attribute or to a new edge attribute column.

Usage

rescale_edge_attrs(graph, edge_attr_from, to_lower_bound = 0,
  to_upper_bound = 1, edge_attr_to = NULL, from_lower_bound = NULL,
  from_upper_bound = NULL)

Arguments

graph

a graph object of class dgr_graph.

edge_attr_from

the edge attribute containing numeric data that is to be rescaled to new numeric or color values.

to_lower_bound

the lower bound value for the set of rescaled values. This can be a numeric value or an X11 color name.

to_upper_bound

the upper bound value for the set of rescaled values. This can be a numeric value or an X11 color name.

edge_attr_to

an optional name of a new edge attribute to which the recoded values will be applied. This will retain the original edge attribute and its values.

from_lower_bound

an optional, manually set lower bound value for the rescaled values. If not set, the minimum value from the set will be used.

from_upper_bound

an optional, manually set upper bound value for the rescaled values. If not set, the minimum value from the set will be used.

Value

a graph object of class dgr_graph.

Examples

# NOT RUN {
# Create a random graph
graph <-
  create_random_graph(
    n = 5, m = 7,
    set_seed = 23,
    directed = TRUE) %>%
  set_edge_attrs(
    edge_attr = weight,
    values = rnorm(edge_count(.), 5))

# Get the graph's internal edf
# to show which edge attributes
# are available
get_edge_df(graph)
#>   id from to  rel   weight
#> 1  1    2  3 <NA> 5.218288
#> 2  2    3  5 <NA> 3.953465
#> 3  3    3  4 <NA> 4.711311
#> 4  4    2  4 <NA> 5.481550
#> 5  5    2  5 <NA> 3.783624
#> 6  6    4  5 <NA> 5.308137
#> 7  7    1  4 <NA> 4.479822

# Rescale the `weight` edge
# attribute, so that its values
# are rescaled between 0 and 1
graph <-
  graph %>%
  rescale_edge_attrs(
    edge_attr_from = weight)

# Get the graph's internal edf
# to show that the edge attribute
# values had been rescaled
get_edge_df(graph)
#>   id from to  rel weight
#> 1  1    2  3 <NA>  0.845
#> 2  2    3  5 <NA>  0.100
#> 3  3    3  4 <NA>  0.546
#> 4  4    2  4 <NA>  1.000
#> 5  5    2  5 <NA>  0.000
#> 6  6    4  5 <NA>  0.898
#> 7  7    1  4 <NA>  0.410

# Scale the values in the `weight`
# edge attribute to different
# shades of gray for the `color`
# edge attribute and different
# numerical values for the
# `penwidth` attribute
graph <-
  graph %>%
  rescale_edge_attrs(
    edge_attr_from = weight,
    to_lower_bound = "gray80",
    to_upper_bound = "gray20",
    edge_attr_to = color) %>%
  rescale_edge_attrs(
    edge_attr_from = weight,
    to_lower_bound = 0.5,
    to_upper_bound = 3,
    edge_attr_to = penwidth)

# Get the graph's internal edf
# once more to show that scaled
# grayscale colors are now available
# in `color` and scaled numerical
# values are in the `penwidth`
# edge attribute
get_edge_df(graph)
#>   id from to  rel weight   color penwidth
#> 1  1    2  3 <NA>  0.845 #484848    2.612
#> 2  2    3  5 <NA>  0.100 #BBBBBB    0.750
#> 3  3    3  4 <NA>  0.546 #747474    1.865
#> 4  4    2  4 <NA>  1.000 #333333    3.000
#> 5  5    2  5 <NA>  0.000 #CCCCCC    0.500
#> 6  6    4  5 <NA>  0.898 #414141    2.745
#> 7  7    1  4 <NA>  0.410 #898989    1.525
# }