title
sud (subset, covariates/line adjustment)

laby

by: level 1

by: level 2

by: level 3

labx
note (variables split, error bars type, line type).

splot(laby ~ labx * by * bet1 * bet2)

general settings

labels	Hide all labels with `FALSE`
labels.filter	Filter out strings from label text. Default is `'_\|\\.'`, which replaces underscores and periods with blank spaces.
labels.trim	Truncate labels that are longer than the set number of characters, or prevent truncation with `FALSE`.
levels	Rename or reorder the levels that appear in the legend or panels (e.g., `levels = list(by = c('a','b','c'))`; see the full documentation for more).
lvn	Hide the variable names before the legend and panel labels with `FALSE`.
mv.as.x	When `y` has multiple variables, `by` is used to list their names (so they appear in the legend). Move these to `x` with `TRUE`.
bg, fg	Change the background or text colors with a code or name (e.g., `bg = '#c9c9c9'`). `fg` applies to label texts.
oma	Adjust the spacing around the plot window: `c(bottom, left, top, right)`, e.g., `oma = c(3, 2, 3, 2)`.

plot panels

sub	Hide the label at the top of each panel with `FALSE`.
ndisp	Hide just the n display in the panel label with `FALSE`.
myl, mxl	Adjust the range of the y- and x-axis, e.g., `myl = c(0, 10)`.
ylas, xlas	Change the orientation of the axis labels (the numbers or level names on each axis). 0 = parallel to axis, 1 = horizontal, 2 = perpendicular to axis, 3 = vertical.
font.axis, font.sub	Change the font by a code. Generally, 1 = plain, 2 = bold, 3 = italic, 4 = bold italic.
cex.axis, cex.sub	Change the font size of axis labels by the set magnification factor.
col.axis, col.sub	Change label colors with a code or name (e.g., `col.axis = '#303030'`). `col.axis` applies to axis labels and lines/tick marks. `col.main` applies to the panel labels.
pch, cex	Change the points' style (e.g., `pch = 1`) or size (e.g., `cex = c(points = 2)`).
drop	`drop['bet']` can affect the layout of panels; e.g., `drop = c(bet = FALSE)` will show empty panels if there are levels of `between` without data.
mfrow	Specifies the number of rows and column. This is normally set based on the levels of `between`, but can be overwritten (e.g., `mfrow = c(2, 3)` would make a layout of 2 rows and 3 columns).
mar	Adjust the spacing between the labels and the plotting area: `c(bottom, left, top, right)`, e.g., `mar = c(1, 1, 3, 0).`

legend

leg	Hide the legend with `FALSE`. Move the legend outside of the plot panels with a string matching `'outside'`, or inside the plot panels with any other string (e.g., `'inside'`). If The legend is outside and there are empty plot panels, the legend will be placed in the empty frame; in this case, a number will specify which panel the legend is placed in.
lpos	Set the position of the legend with a keyword (e.g., `'topleft'` or `'center'`), or place it with a click with `'place'`. If not specified, this is done automatically.
leg.title	Turn off the title above the legend with `FALSE`, or enter a custom title in quotes.
prat	When the legend is outside (as here), this will adjust the ratio between the plot panels and the legend (e.g., `prat = c(2, 1)`, where the first value applies to each plot panels, and the second to the legend).
font	Change the font of the legend title or labels, e.g., `font = c(leg.title = 4, leg = 3)`.
cex	Change the font size, e.g., `cex = c(leg = 3)`.
drop	`drop['by']` can affect which labels appear in the legend; e.g., `drop = c(by = FALSE)` will show labels for all levels of `by`, even if some have no data.
leg.args	A list passing additional arguments to legend (see ?legend).