Facet a ggplot into Multiple Panels

Source: R/facet.R

Create multi-panel plots of a data set grouped by one or two grouping variables. Wrapper around facet_wrap

facet(
  p,
  facet.by,
  nrow = NULL,
  ncol = NULL,
  scales = "fixed",
  short.panel.labs = TRUE,
  labeller = "label_value",
  panel.labs = NULL,
  panel.labs.background = list(color = NULL, fill = NULL),
  panel.labs.font = list(face = NULL, color = NULL, size = NULL, angle = NULL),
  panel.labs.font.x = panel.labs.font,
  panel.labs.font.y = panel.labs.font,
  strip.position = "top",
  ...
)

Arguments

p

a ggplot

facet.by

character vector, of length 1 or 2, specifying grouping variables for faceting the plot into multiple panels. Should be in the data.

nrow, ncol

Number of rows and columns in the panel. Used only when the data is faceted by one grouping variable.

scales

should axis scales of panels be fixed ("fixed", the default), free ("free"), or free in one dimension ("free_x", "free_y").

short.panel.labs

logical value. Default is TRUE. If TRUE, create short labels for panels by omitting variable names; in other words panels will be labelled only by variable grouping levels.

labeller

Character vector. An alternative to the argument short.panel.labs. Possible values are one of "label_both" (panel labelled by both grouping variable names and levels) and "label_value" (panel labelled with only grouping levels).

panel.labs

a list of one or two character vectors to modify facet panel labels. For example, panel.labs = list(sex = c("Male", "Female")) specifies the labels for the "sex" variable. For two grouping variables, you can use for example panel.labs = list(sex = c("Male", "Female"), rx = c("Obs", "Lev", "Lev2") ).

panel.labs.background

a list to customize the background of panel labels. Should contain the combination of the following elements:

  • color, linetype, size: background line color, type and size

  • fill: background fill color.

For example, panel.labs.background = list(color = "blue", fill = "pink", linetype = "dashed", size = 0.5).

panel.labs.font

a list of aestheics indicating the size (e.g.: 14), the face/style (e.g.: "plain", "bold", "italic", "bold.italic") and the color (e.g.: "red") and the orientation angle (e.g.: 45) of panel labels.

panel.labs.font.x, panel.labs.font.y

same as panel.labs.font but for only x and y direction, respectively.

strip.position

(used only in facet_wrap()). By default, the labels are displayed on the top of the plot. Using strip.position it is possible to place the labels on either of the four sides by setting strip.position = c("top", "bottom", "left", "right")

...

not used

Examples

p <- ggboxplot(ToothGrowth, x = "dose", y = "len",
      color = "supp")
print(p)


facet(p, facet.by = "supp")


# Customize
facet(p + theme_bw(), facet.by = "supp",
  short.panel.labs = FALSE,   # Allow long labels in panels
  panel.labs.background = list(fill = "steelblue", color = "steelblue")
)