hist.data.frame: Histograms for Variables in a Data Frame

Description

This functions tries to compute the maximum number of histograms that
will fit on one page, then it draws a matrix of histograms. If there
are more qualifying variables than will fit on a page, the function
waits for a mouse click before drawing the next page.

minimum number of unique values a variable must have
before a histogram is drawn

nclass

number of bins. Default is
max(2,trunc(min(n/10,25*log(n,10))/2)), where n is the number of
non-missing values for a variable.

na.big

set to TRUE to draw the number of missing values
on the top of the histogram in addition to in a subtitle. In the
subtitle, n is the number of non-missing values and m is the number
of missing values

rugs

set to TRUE to add rug plots at the top of each
histogram