Obtain a plot of the pattern of missing data and/or return the pattern as a matrix.
data frame
vector of length two, that specifies the colour used to indicate observed and missing values (in that order)
colour of the grid
logical; should the missing data pattern be plotted?
(default is TRUE)
logical; should the missing data pattern be returned as
matrix? (default is FALSE)
logical; should the x-axis (below the plot) and y-axis (on the right) be printed?
y-axis label
the default position of legends ("none", "left", "right", "bottom", "top", "inside")
logical; should the columns be sorted by number of missing
values? (default is TRUE)
optional additional parameters, currently not used
This function requires the ggplot2 package to be installed.
See the vignette Visualizing Incomplete Data for more examples.