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 itemMatrix
itemFrequencyPlot(x, type = c("relative", "absolute"),
weighted = FALSE, support = NULL, topN = NULL,
population = NULL, popCol = "black", popLwd = 1,
lift = FALSE, horiz = FALSE,
names = TRUE, cex.names = graphics::par("cex.axis"),
xlab = NULL, ylab = NULL, mai = NULL, …)
the object to be plotted.
further arguments are passed on (see
barplot
from possible arguments).
a character string indicating whether item frequencies should be displayed relative of absolute.
should support be weighted by transactions weights stored
as column "weight"
in transactionInfo?
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
.
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.
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.
plotting color for population.
line width for population.
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
.
a logical. If horiz = FALSE
(default),
the bars are drawn vertically. If TRUE
, the bars are
drawn horizontally.
a logical indicating if the names (bar labels) should be displayed?
a numeric value for the expansion factor for axis names (bar labels).
a character string with the label for the x axis (use an empty string to force no label).
a character string with the label for the y axis (see xlab).
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.
# NOT RUN {
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)
# }
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