QQ Plots

Quantile-Quantile plot.

ggqqplot(
  data,
  x,
  combine = FALSE,
  merge = FALSE,
  color = "black",
  palette = NULL,
  size = NULL,
  shape = NULL,
  add = c("qqline", "none"),
  add.params = list(linetype = "solid"),
  conf.int = TRUE,
  conf.int.level = 0.95,
  title = NULL,
  xlab = NULL,
  ylab = NULL,
  facet.by = NULL,
  panel.labs = NULL,
  short.panel.labs = TRUE,
  ggtheme = theme_pubr(),
  ...
)

Arguments

data: a data frame
x: variable to be drawn.
combine: logical value. Default is FALSE. Used only when y is a vector containing multiple variables to plot. If TRUE, create a multi-panel plot by combining the plot of y variables.
merge: logical or character value. Default is FALSE. Used only when y is a vector containing multiple variables to plot. If TRUE, merge multiple y variables in the same plotting area. Allowed values include also "asis" (TRUE) and "flip". If merge = "flip", then y variables are used as x tick labels and the x variable is used as grouping variable.
color: point color.
palette: the color palette to be used for coloring or filling by groups. Allowed values include "grey" for grey color palettes; brewer palettes e.g. "RdBu", "Blues", ...; or custom color palette e.g. c("blue", "red"); and scientific journal palettes from ggsci R package, e.g.: "npg", "aaas", "lancet", "jco", "ucscgb", "uchicago", "simpsons" and "rickandmorty".
size: point size.
shape: point shape.
add: character vector. Allowed values are one of "none" and "qqline" (for adding qqline).
add.params: parameters (color, size, linetype) for the argument 'add'; e.g.: add.params = list(color = "red").
conf.int: logical value. If TRUE, confidence interval is added.
conf.int.level: the confidence level. Default value is 0.95.
title: plot main title.
xlab: character vector specifying x axis labels. Use xlab = FALSE to hide xlab.
ylab: character vector specifying y axis labels. Use ylab = FALSE to hide ylab.
facet.by: character vector, of length 1 or 2, specifying grouping variables for faceting the plot into multiple panels. Should be in the data.
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") ).
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.
ggtheme: function, ggplot2 theme name. Default value is theme_pubr(). Allowed values include ggplot2 official themes: theme_gray(), theme_bw(), theme_minimal(), theme_classic(), theme_void(), ....
...: other arguments to be passed to ggpar.

Details

The plot can be easily customized using the function ggpar(). Read ?ggpar for changing:

main title and axis labels: main, xlab, ylab
axis limits: xlim, ylim (e.g.: ylim = c(0, 30))
axis scales: xscale, yscale (e.g.: yscale = "log2")
color palettes: palette = "Dark2" or palette = c("gray", "blue", "red")
legend title, labels and position: legend = "right"
plot orientation : orientation = c("vertical", "horizontal", "reverse")

Examples

# Create some data format
set.seed(1234)
wdata = data.frame(
   sex = factor(rep(c("F", "M"), each=200)),
   weight = c(rnorm(200, 55), rnorm(200, 58)))

head(wdata, 4)
#>   sex   weight
#> 1   F 53.79293
#> 2   F 55.27743
#> 3   F 56.08444
#> 4   F 52.65430

# Basic QQ plot
ggqqplot(wdata, x = "weight")


# Change colors and shape by groups ("sex")
# Use custom palette
ggqqplot(wdata, x = "weight",
   color = "sex", palette = c("#00AFBB", "#E7B800"))

Arguments

Details

See also

Examples