Alluvial plots consist of multiple horizontally-distributed columns (axes) representing factor variables, vertical divisions (strata) of these axes representing these variables' values; and splines (alluvial flows) connecting vertical subdivisions (lodes) within strata of adjacent axes representing subsets or amounts of observations that take the corresponding values of the corresponding variables. This function checks a data frame for either of two types of alluvial structure:

is_lodes_form(
  data,
  key,
  value,
  id,
  weight = NULL,
  logical = TRUE,
  silent = FALSE
)

is_alluvia_form(
  data,
  ...,
  axes = NULL,
  weight = NULL,
  logical = TRUE,
  silent = FALSE
)

to_lodes_form(
  data,
  ...,
  axes = NULL,
  key = "x",
  value = "stratum",
  id = "alluvium",
  diffuse = FALSE,
  discern = FALSE
)

to_alluvia_form(data, key, value, id, distill = FALSE)

Arguments

data

A data frame.

key, value, id

In to_lodes_form, handled as in tidyr::gather() and used to name the new axis (key), stratum (value), and alluvium (identifying) variables. In to_alluvia_form, handled as in tidyr::spread() and used to identify the fields of data to be used as the axis (key), stratum (value), and alluvium (identifying) variables.

weight

Optional field of data, handled using rlang::enquo(), to be used as heights or depths of the alluvia or lodes.

logical

Defunct. Whether to return a logical value or a character string indicating the type of alluvial structure ("none", "lodes", or "alluvia").

silent

Whether to print messages.

...

Used in is_alluvia_form and to_lodes_form as in dplyr::select() to determine axis variables, as an alternative to axes. Ignored when axes is provided.

axes

In *_alluvia_form, handled as in dplyr::select() and used to identify the field(s) of data to be used as axes.

diffuse

Fields of data, handled using tidyselect::vars_select(), to merge into the reshapen data by id. They must be a subset of the axis variables. Alternatively, a logical value indicating whether to merge all (TRUE) or none (FALSE) of the axis variables.

discern

Logical value indicating whether to suffix values of the variables used as axes that appear at more than one variable in order to distinguish their factor levels. This forces the levels of the combined factor variable value to be in the order of the axes.

distill

A logical value indicating whether to include variables, other than those passed to key and value, that vary within values of id. Alternatively, a function (or its name) to be used to distill each such variable to a single value. In addition to existing functions, distill accepts the character values "first" (used if distill is TRUE), "last", and "most" (which returns the modal value).

Details

  • One row per lode, wherein each row encodes a subset or amount of observations having a specific profile of axis values, a key field encodes the axis, a value field encodes the value within each axis, and a id column identifies multiple lodes corresponding to the same subset or amount of observations. is_lodes_form tests for this structure.

  • One row per alluvium, wherein each row encodes a subset or amount of observations having a specific profile of axis values and a set axes of fields encodes its values at each axis variable. is_alluvia_form tests for this structure.

to_lodes_form takes a data frame with several designated variables to be used as axes in an alluvial plot, and reshapes the data frame so that the axis variable names constitute a new factor variable and their values comprise another. Other variables' values will be repeated, and a row-grouping variable can be introduced. This function invokes tidyr::gather().

to_alluvia_form takes a data frame with axis and axis value variables to be used in an alluvial plot, and reshape the data frame so that the axes constitute separate variables whose values are given by the value variable. This function invokes tidyr::spread().

See also

Other alluvial data manipulation: self-adjoin

Examples

# Titanic data in alluvia format titanic_alluvia <- as.data.frame(Titanic) head(titanic_alluvia)
#> Class Sex Age Survived Freq #> 1 1st Male Child No 0 #> 2 2nd Male Child No 0 #> 3 3rd Male Child No 35 #> 4 Crew Male Child No 0 #> 5 1st Female Child No 0 #> 6 2nd Female Child No 0
is_alluvia_form(titanic_alluvia, weight = "Freq")
#> [1] TRUE
# Titanic data in lodes format titanic_lodes <- to_lodes_form(titanic_alluvia, key = "x", value = "stratum", id = "alluvium", axes = 1:4) head(titanic_lodes)
#> Freq alluvium x stratum #> 1 0 1 Class 1st #> 2 0 2 Class 2nd #> 3 35 3 Class 3rd #> 4 0 4 Class Crew #> 5 0 5 Class 1st #> 6 0 6 Class 2nd
is_lodes_form(titanic_lodes, key = "x", value = "stratum", id = "alluvium", weight = "Freq")
#> [1] TRUE
# again in lodes format, this time diffusing the `Class` variable titanic_lodes2 <- to_lodes_form(titanic_alluvia, key = variable, value = value, id = passenger, 1:3, diffuse = Class) head(titanic_lodes2)
#> passenger Class Survived Freq variable value #> 1 1 1st No 0 Class 1st #> 2 1 1st No 0 Sex Male #> 3 1 1st No 0 Age Child #> 4 2 2nd No 0 Class 2nd #> 5 2 2nd No 0 Sex Male #> 6 2 2nd No 0 Age Child
is_lodes_form(titanic_lodes2, key = variable, value = value, id = passenger, weight = Freq)
#> [1] TRUE
# curriculum data in lodes format data(majors) head(majors)
#> student semester curriculum #> 1 1 CURR1 Painting #> 2 2 CURR1 Painting #> 3 6 CURR1 Sculpure #> 4 8 CURR1 Painting #> 5 9 CURR1 Sculpure #> 6 10 CURR1 Painting
is_lodes_form(majors, key = "semester", value = "curriculum", id = "student")
#> [1] TRUE
# curriculum data in alluvia format majors_alluvia <- to_alluvia_form(majors, key = "semester", value = "curriculum", id = "student") head(majors_alluvia)
#> student CURR1 CURR3 CURR5 CURR7 CURR9 CURR11 CURR13 #> 1 1 Painting Painting Painting Painting Painting Painting Painting #> 2 2 Painting Painting Painting Painting Painting Painting <NA> #> 3 6 Sculpure Sculpure Painting Painting Painting Painting Painting #> 4 8 Painting Painting Painting Painting <NA> Painting Painting #> 5 9 Sculpure Art History Art History Painting Painting Painting Painting #> 6 10 Painting Painting Painting Painting Painting Painting <NA> #> CURR15 #> 1 Painting #> 2 <NA> #> 3 Painting #> 4 Painting #> 5 Painting #> 6 <NA>
is_alluvia_form(majors_alluvia, tidyselect::starts_with("CURR"))
#> Missing alluvia for some stratum combinations.
#> [1] TRUE
# distill variables that vary within `id` values set.seed(1) majors$hypo_grade <- LETTERS[sample(5, size = nrow(majors), replace = TRUE)] majors_alluvia2 <- to_alluvia_form(majors, key = "semester", value = "curriculum", id = "student", distill = "most")
#> Distilled variables: hypo_grade
head(majors_alluvia2)
#> student hypo_grade CURR1 CURR3 CURR5 CURR7 CURR9 #> 1 1 A Painting Painting Painting Painting Painting #> 2 2 D Painting Painting Painting Painting Painting #> 3 6 B Sculpure Sculpure Painting Painting Painting #> 4 8 B Painting Painting Painting Painting <NA> #> 5 9 E Sculpure Art History Art History Painting Painting #> 6 10 A Painting Painting Painting Painting Painting #> CURR11 CURR13 CURR15 #> 1 Painting Painting Painting #> 2 Painting <NA> <NA> #> 3 Painting Painting Painting #> 4 Painting Painting Painting #> 5 Painting Painting Painting #> 6 Painting <NA> <NA>
# options to distinguish strata at different axes gg <- ggplot(majors_alluvia, aes(axis1 = CURR1, axis2 = CURR7, axis3 = CURR13)) gg + geom_alluvium(aes(fill = as.factor(student)), width = 2/5, discern = TRUE) + geom_stratum(width = 2/5, discern = TRUE) + geom_text(stat = "stratum", discern = TRUE, infer.label = TRUE)
gg + geom_alluvium(aes(fill = as.factor(student)), width = 2/5, discern = FALSE) + geom_stratum(width = 2/5, discern = FALSE) + geom_text(stat = "stratum", discern = FALSE, infer.label = TRUE)
# warning when inappropriate ggplot(majors[majors$semester %in% paste0("CURR", c(1, 7, 13)), ], aes(x = semester, stratum = curriculum, alluvium = student, label = curriculum)) + geom_alluvium(aes(fill = as.factor(student)), width = 2/5, discern = TRUE) + geom_stratum(width = 2/5, discern = TRUE) + geom_text(stat = "stratum", discern = TRUE)
#> Warning: Data is already in lodes format, so `discern` will be ignored.
#> Warning: Data is already in lodes format, so `discern` will be ignored.
#> Warning: Data is already in lodes format, so `discern` will be ignored.
#> Warning: Removed 1 rows containing missing values (geom_text).