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Sankey Diagram for Categorical Variables

Source: R/plt_sankey.R
plt_sankey.Rd

Visualise the flow/proportion changes across multiple categorical variables using a Sankey (alluvial) diagram. Each node label shows the level name, count, and percentage.

Usage

plt_sankey(
  data,
  vars,
  palette = NULL,
  reverse_levels = TRUE,
  show_n = TRUE,
  width = 0.4,
  label_size = 3,
  label_hjust = 0.5,
  alpha = 0.6,
  base_size = 14
)

Arguments

data

A data frame.

vars

Character vector of categorical variable names (>= 2). Variables are displayed left-to-right in the given order.

palette

Colour palette name from pal_get(), or a character vector of colours. Default NULL auto-generates colours per variable using sequential HCL palettes.

reverse_levels

Logical, reverse factor levels for display. Default TRUE.

show_n

Logical, show count in node labels. Default TRUE.

width

Sankey node width. Default 0.4.

label_size

Label text size. Default 3.

label_hjust

Label horizontal justification. Default 0.5.

alpha

Flow transparency. Default 0.6.

base_size

Base font size. Default 14.

Value

A ggplot object.

Note

Requires the ggsankey package (pak::pak("davidsjoberg/ggsankey")).

See also

Other plot: PlotButterfly(), PlotButterfly2(), PlotRankCor(), plt_cat(), plt_cohen(), plt_con(), plt_dist(), plt_radar(), plt_upset()

Examples

df <- data.frame(
  sex = factor(sample(c("M","F"), 200, TRUE)),
  stage = factor(sample(c("I","II","III"), 200, TRUE)),
  grade = factor(sample(c("Low","High"), 200, TRUE))
)

# Basic sankey
plt_sankey(df, vars = c("sex", "stage", "grade"))
#> Warning: attributes are not identical across measure variables; they will be dropped
#> Warning: The `size` argument of `element_rect()` is deprecated as of ggplot2 3.4.0.
#> ℹ Please use the `linewidth` argument instead.
#> ℹ The deprecated feature was likely used in the ggsankey package.
#>   Please report the issue at <https://github.com/davidsjoberg/ggsankey/issues>.


# Two variables
plt_sankey(df, vars = c("sex", "stage"))
#> Warning: attributes are not identical across measure variables; they will be dropped


# Custom palette
plt_sankey(df, vars = c("sex", "stage"), palette = "Paired")
#> Warning: attributes are not identical across measure variables; they will be dropped


# Without counts in labels
plt_sankey(df, vars = c("sex", "stage", "grade"), show_n = FALSE)
#> Warning: attributes are not identical across measure variables; they will be dropped


# Adjust appearance
plt_sankey(df, vars = c("sex", "stage"),
           width = 0.3, label_size = 4, alpha = 0.4)
#> Warning: attributes are not identical across measure variables; they will be dropped