itemFrequencyPlot {arules} | R Documentation |
Provides the generic function itemFrequencyPlot
and the S4 method to
create an item frequency bar plot for inspecting the item frequency
distribution for objects based on itemMatrix
(e.g.,
transactions
, or items in itemsets
and rules
).
itemFrequencyPlot(x, ...) ## S4 method for signature 'itemMatrix': itemFrequencyPlot(x, type = c("relative", "absolute"), support = NULL, topN = NULL, population = NULL, popCol = "black", popLwd = 1, lift = FALSE, horiz = FALSE, names = TRUE, cex.names = par("cex.axis"), xlab = NULL, ylab = NULL, mai = NULL, ...)
x |
the object to be plotted. |
... |
further arguments are passed on (see
barplot from possible arguments). |
type |
a character string indicating whether item frequencies should be displayed relative of absolute. |
support |
a numeric value. Only display items which have a support of
at least support . If no population is given, support is calculated
from x otherwise from the population. Support is interpreted relative
or absolute according to the setting of type . |
topN |
a integer value. Only plot the topN
items with the highest item frequency or lift (if lift = TRUE ).
The items are plotted ordered by descending support. |
population |
object of same class as x ; if x
is a segment of a population, the population mean frequency for
each item can be shown as a line in the plot. |
popCol |
plotting color for population. |
popLwd |
line width for population. |
lift |
a logical indicating whether to plot the lift ratio between
instead of frequencies. The lift ratio is gives how many times an item is
more frequent in x than in population . |
horiz |
a logical. If horiz = FALSE (default),
the bars are drawn vertically. If TRUE , the bars are
drawn horizontally. |
names |
a logical indicating if the names (bar labels) should be displayed? |
cex.names |
a numeric value for the expansion factor for axis names (bar labels). |
xlab |
a character string with the label for the x axis (use an empty string to force no label). |
ylab |
a character string with the label for the y axis (see xlab). |
mai |
a numerical vector giving the plots margin sizes in inches (see `? par'). |
A numeric vector with the midpoints of the drawn bars; useful for adding to the graph.
itemFrequency
,
itemMatrix-class
data(Adult) ## the following example compares the item frequencies ## of people with a large income (boxes) with the average in the data set Adult.largeIncome <- Adult[Adult %in% "income=large"] ## simple plot itemFrequencyPlot(Adult.largeIncome) ## plot with the averages of the population plotted as a line ## (for first 72 variables/items) itemFrequencyPlot(Adult.largeIncome[, 1:72], population = Adult[, 1:72]) ## plot lift ratio (frequency in x / frequency in population) ## for items with a support of 20% in the population itemFrequencyPlot(Adult.largeIncome, population = Adult, support = 0.2, lift = TRUE, horiz = TRUE)