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lessR (version 3.4.6)

LineChart: Line Chart such as a Run Chart or Time-Series Chart

Description

Abbreviation: lc

Plots a line chart, the values of the variable ordered according to their order in the data frame. Usually this ordering would be an ordering according to time, which yields a run chart. The default run chart provides the index, that is, sequential position, of each value of the variable from 1 to the last value. Optionally dates can be provided so that a time-series plot is produced.

For data of one variable exhibiting little trend, the center line is provided for the generation of a run chart, plotting the values of a variable in order of occurrence over time. When the center line, the median by default, is plotted, the analyses of the number and composition of the individual runs, number of consecutive values above or below the center line, is also displayed. Also, the defaults change for each of the types of plots. The intent is to rely on the default values for a relatively sophisticated plot, particularly when compared to the default values of the standard R plot function called with a single variable.

If the provided object to analyze is a set of multiple variables, including an entire data frame, then each non-numeric variable in the data frame is analyzed and the results written to a pdf file in the current working directory. The name of each output pdf file that contains a bar chart and its path are specified in the output.

Usage

LineChart(x, data=mydata, n.cat=getOption("n.cat"), type=NULL, 

col.fill=getOption("col.fill.bar"), col.stroke=getOption("col.stroke.pt"), col.bg=getOption("col.bg"), col.grid=getOption("col.grid"), col.line=getOption("col.stroke.pt"),

col.area=NULL, col.box="black",

shape.pts=21, cex.axis=.75, col.axis="gray30",

rotate.values=0, offset=.5,

xy.ticks=TRUE, line.width=1.1, xlab=NULL, ylab=NULL, main=NULL, sub=NULL, cex=NULL,

time.start=NULL, time.by=NULL, time.reverse=FALSE,

center.line=c("default", "mean", "median", "zero", "off"),

show.runs=FALSE, quiet=getOption("quiet"), pdf.file=NULL, pdf.width=5, pdf.height=5, ...)

lc(...)

Arguments

x
Variable(s) to analyze. Can be a single numerical variable, either within a data frame or as a vector in the user's workspace, or multiple variables in a data frame such as designated with the c
data
Optional data frame that contains the variable(s) of interest, default is mydata.
n.cat
For the analysis of multiple variables, such as a data frame, specifies the largest number of unique values of variable of a numeric data type for which the variable will be analyzed as a categorical. Default is 0.
type
Character string that indicates the type of plot, either "p" for points, "l" for line, or "b" for both. The default is "b" for both points and lines.
col.fill
For plotted points, the interior color of the point. For a scatterplot the default value is transparent. For a run chart the default value is the color of the point's border, col.stroke.
col.stroke
Color of the border of the plotted points.
col.bg
Color of the plot background.
col.grid
Color of the grid lines, with a default of "grey90".
col.line
Color of any plotted line segments, with a default of "darkblue".
col.area
Color of area under the plotted line segments, which by default is not applied, equivalent to a color of "transparent".
col.box
Color of border around the plot background, the box, that encloses the plot, with a default of "black".
shape.pts
The standard plot character, with values defined in help(points). The default value is 21, a circle with both a border and filled area, specified here as col.stroke and col.fill. col.fill defaults to
cex.axis
Scale magnification factor, which by defaults displays the axis values to be smaller than the axis labels.
col.axis
Color of the font used to label the axis values.
rotate.values
Degrees that the axis values are rotated, usually to accomodate longer values, typically used in conjunction with offset.
offset
The amount of spacing between the axis values and the axis. Default is 0.5. Larger values such as 1.0 are used to create space for the label when longer axis value names are rotated.
xy.ticks
Flag that indicates if tick marks and associated values on the axes are to be displayed.
line.width
Width of the density lines.
xlab
Label for x-axis. For two variables specified, x and y, if xlab not specified, then the label becomes the name of the corresponding variable. If xy.ticks is FALSE, then no label is displayed. If no y v
ylab
Label for y-axis. If not specified, then the label becomes the name of the corresponding variable. If xy.ticks is FALSE, then no label displayed.
main
Label for the title of the graph. If the corresponding variable labels exist, then the title is set by default from the corresponding variable labels.
sub
Sub-title of graph, below xlab.
cex
Magnification factor for any displayed points, with default of cex=1.0.
time.start
Optional starting date for first data value. Format must be "%Y-%m-%d" or "%Y/%m/%d". If using with x.reverse, the first date is after the data are reverse sorted. Not needed if data are a time series with
time.by
Accompanies the time.start specification, the interval to increment the date for each sequential data value. A character string, containing one of "day", "week", "month" or "year"
time.reverse
When TRUE, reverse the ordering of the dates, particularly when the data are listed such that first row of data is the newest. Accompanies the time.start specification.
center.line
Plots a dashed line through the middle of a run chart. The two possible values for the line are "mean" and "median". Provides a centerline for the "median" by default when the values randomly vary about
show.runs
If TRUE, display the individual runs in the run analysis.
quiet
If set to TRUE, no text output. Can change system default with set function.
pdf.file
Name of the pdf file to which graphics are redirected. If there is no filetype of .pdf, the filetype is added to the name.
pdf.width
Width of the pdf file in inches.
pdf.height
Height of the pdf file in inches.
...
Other parameters such as from par, col.lab, sub, col.sub, col.ticks to set the color of the ticks used to label the axis values, and <

Details

OVERVIEW The line chart is based on the standard R function plot when called with only a single variable.

The values on the horizontal axis of the line chart are automatically generated. The default is the index variable, the ordinal position of each data value, in which case this version of the line chart is a run chart. Or, dates on the horizontal axis can be specified from the specified starting date given by x.start and the accompanying increment as given by x.by, in which case the line chart is typically referred to as a time series chart.

If the data values randomly vary about the mean, the default is to plot the mean as the center line of the graph, otherwise the default is to ignore the center line. The default plot type for the line chart is type="b", for both points and the corresponding connected line segments. The size of the points is automatically reduced according to the number of points of points plotted, and the cex option can override the computed default. If the area below the plotted values is specified to be filled in with color, then the default line type changes to type="l".

DATA The data may either be a vector from the global environment, the user's workspace, as illustrated in the examples below, or one or more variable's in a data frame, or a complete data frame. The default input data frame is mydata. Can specify the source data frame name with the data option. If multiple variables are specified, only the numerical variables in the list of variables are analyzed. The variables in the data frame are referenced directly by their names, that is, no need to invoke the standard R mechanisms of the mydata$name notation, the with function or the attach function. If the name of the vector in the global environment and of a variable in the input data frame are the same, the vector is analyzed.

COLORS Individual colors in the plot can be manipulated with options such as col.stroke for the color of the border of the plotted points. A color theme for all the colors can be chosen for a specific plot with the colors option with the lessR function set. The default color theme is dodgerblue, but a gray scale is available with "gray", and other themes are available as explained in set, such as "red" and "green". Use the option ghost=TRUE for a black background, no grid lines and partial transparency of plotted colors.

VARIABLE LABELS Although standard R does not provide for variable labels, lessR does, obtained from the Read function. If the variable labels exist, then the corresponding variable label is by default listed as the label for the horizontal axis and on the text output. For more information, see Read.

PDF OUTPUT Because of the customized graphic windowing system that maintains a unique graphic window for the Help function, the standard graphic output functions such as pdf do not work with the lessR graphics functions. Instead, to obtain pdf output, use the pdf.file option, perhaps with the optional pdf.width and pdf.height options. These files are written to the default working directory, which can be explicitly specified with the R setwd function.

ONLY VARIABLES ARE REFERENCED The referenced variable in a lessR function can only be a variable name (or list of variable names). This referenced variable must exist in either the referenced data frame, such as the default mydata, or in the user's workspace, more formally called the global environment. That is, expressions cannot be directly evaluated. For example:

> LineChart(rnorm(50)) # does NOT work}

Instead, do the following: > Y <- rnorm(50) # create vector Y in user workspace > LineChart(Y) # directly reference Y

[object Object],[object Object]

plot, set.

# create data frame, mydata, to mimic reading data with Read function # mydata contains both numeric and non-numeric data mydata <- data.frame(rnorm(50), rnorm(50), rnorm(50), rep(c("A","B"),25)) names(mydata) <- c("X","Y","Z","C")

# default run chart LineChart(Y) # short name lc(Y) # compare to standard R plot plot(mydata$Y, type="l")

# save run chart to a pdf file LineChart(Y, pdf.file="MyLineChart.pdf")

# LineChart in gray scale, then back to default "dodgerblue" theme(colors="gray") LineChart(Y) theme(colors="dodgerblue") # customize run chart with LineChart options LineChart(Y, line.width=2, col.stroke="sienna3", col.area="slategray3", col.bg="mintcream", center.line="median")

# customize run chart with R par parameters # 24 is the R value for a half-triangle pointing up lc(Y, xlab="My xaxis", ylab="My yaxis", main="My Best Title", cex.axis=.7, cex.lab=1.2, cex.main=1.5, col.lab="red", font.main=3, ylim=c(-4,4), shape.pts=24) # generate steadily increasing values Y <- sort(rexp(50)) # default line chart LineChart(Y) # line chart with border around plotted values LineChart(Y, col.area="transparent") # time series chart, i.e., with dates, and filled area # with option label for the x-axis LineChart(Y, time.start="2000/09/01", time.by="3 months") # time series chart from a time series object y.ts <- ts(Y, start=c(2000, 9), frequency=4) LineChart(y.ts)

# LineChart with built-in data set LineChart(breaks, data=warpbreaks)

# Line charts for all numeric variables in a data frame LineChart()

# Line charts for all specified numeric variables in a list of variables # e.g., use the combine or c function to specify a list of variables LineChart(c(X,Y))plot line chart run chart time series chart