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Set the Line Types of Selected Edges

Source: R/set_edge_lty.R
set_edge_line_type.Rd

Set the line types of selected edges.

Usage

set_edge_line_type(
  semPaths_plot,
  line_type_list = NULL,
  check_direction = TRUE
)

Arguments

semPaths_plot

A qgraph::qgraph object generated by semPlot::semPaths, or a similar qgraph object modified by other semptools functions. It can also be a list of qgraph::qgraph objects, probably though not necessarily from a multigroup model. If it is a list of qgraph::qgraph objects, then the function will be applied to all the objects.

line_type_list

A named vector or a list of named list. See the Details section on how to set this argument.

check_direction

If FALSE, the direction of an edge is ignored. For example, both y ~ x and x ~ y will affect y ~ x, x ~ y, and y ~~ x. Useful when we want to change an edge regardless of its direction and whether it is directional.

Value

A qgraph::qgraph based on the original one, with widths for selected edges changed. If semPaths_plot is a list of qgraph::qgraph objects, then a list of processed qgraph::qgraph objects will be returned.

Details

Modified a qgraph::qgraph object generated by semPlot::semPaths and change the widths of selected edges.

Setting the value of line_type_list

This argument can be set in three ways.

For a named vector, the name of an element should be the path as specified by lavaan::model.syntax or as appeared in lavaan::parameterEstimates().

For example, to change the line type of the path regressing y on x, the name should be "y ~ x". To change the line type of the covariance between x1 and x2, the name should be "x1 ~~ x2". Therefore, c("y ~ x1" = "dotted", "x1 ~~ x2" = "dashed") changes the line types of the path from x1 to y and the covariance between x1 and x2 to "dotted" and "dashed", respectively.

The order of the two nodes may matter for covariances. Therefore, if the attribute of a covariance is not changed, try switching the order of the two nodes.

For a list of named lists, each named list should have three named values: from, to, and new_line_type. The attribute of the edge from from to to will be set to new_line_type.

The second approach is no longer recommended, though kept for backward compatibility.

The third approach is one single unnamed value. This value will be applied to all edges.

Supported Line Type

The supported line types are the same line types supported by the lty argument of par(): "blank" (0), "solid" (1), "dashed" (2), "dotted" (3), "dotdash" (4), "longdash" (5), and "twodash" (6). The new line type can be specified in either strings or integers, but not both.

Examples

mod_pa <-
  'x1 ~~ x2
   x3 ~  x1 + x2
   x4 ~  x1 + x3
  '
fit_pa <- lavaan::sem(mod_pa, pa_example)
lavaan::parameterEstimates(fit_pa)[, c("lhs", "op", "rhs", "est", "pvalue")]
#>   lhs op rhs   est pvalue
#> 1  x1 ~~  x2 0.005  0.957
#> 2  x3  ~  x1 0.537  0.000
#> 3  x3  ~  x2 0.376  0.000
#> 4  x4  ~  x1 0.111  0.382
#> 5  x4  ~  x3 0.629  0.000
#> 6  x3 ~~  x3 0.874  0.000
#> 7  x4 ~~  x4 1.194  0.000
#> 8  x1 ~~  x1 0.933  0.000
#> 9  x2 ~~  x2 1.017  0.000
m <- matrix(c("x1",   NA,   NA,
                NA, "x3", "x4",
              "x2",   NA,   NA), byrow = TRUE, 3, 3)
p_pa <- semPlot::semPaths(fit_pa, whatLabels="est",
            style = "ram",
            nCharNodes = 0, nCharEdges = 0,
            layout = m)


my_line_type_vector <- c(
   "x2 ~~ x1" = "dotted",
   "x4 ~ x1" = "dashed"
)

p_pa2v <- set_edge_line_type(
 p_pa,
 my_line_type_vector)
plot(p_pa2v)


my_line_type_list <- list(
   list(
     from = "x1",
     to = "x2",
     new_line_type = "dotted"),
   list(
     from = "x1",
     to = "x4",
     new_line_type =  "dashed")
 )

p_pa2l <- set_edge_line_type(
   p_pa,
   my_line_type_list
 )
plot(p_pa2l)