lessR (version 2.2)

label: Get a Variable Label for Display on Output

Description

Display a variable label for output, either text output at the console or graphics, such as a title on a graph. Generally applies to standard R functions as lessR functions automatically provide varible labels on the output when the labels are present in the mylabels data frame.

Usage

label(x, dframe=mylabels)

Arguments

x

The variable for which to obtain the corresponding variable label.

dframe

Data frame that contains the variable of interest, which is mylabels.

Details

Standard R does not provide for variable labels, but lessR provides for a data frame called mylabels which stores variable labels. Read the labels into this data frame with a version of the rad function. The variable labels can either be in a separate file by themselves, rad.labels, or in the second row of the data file, rad.both. Each row of the file that contains the labels, including the first row, consists of the variable name, a comma, and then the label, that is, standard csv format. Not all variables need have a label, and the variables with their corresponding labels can be listed in any order.

The rad function automatically creates the mylabels data frame. The structure of the data frame consists of the variable names which serve as the row names. The labels themselves are a variable named label, but this information is only necessary if constructing the labels data frame manually, such as is done in the examples.

This function is automatically accessed by the lessR functions that provide data analysis, such as automatically providing the title of a graph as the corresponding variable label. This function can also be added to standard R function calls as well, such as an argument for main in graphics output, where main is the title of the graph.

See Also

rad, plot.

Examples

# create data frame mydata (usually read from a file with rad)
n <- 12
X <- sample(c("Group1","Group2"), size=n, replace=TRUE)
Y <- rnorm(n=n, mean=50, sd=10)
mydata <- data.frame(X,Y)
rm(X); rm(Y);

# create data frame mylabels (usually read from a file with rad)
vname <- character(length=2);  vname[1] <- "X";  vname[2] <- "Y"
label <- character(length=2)
label[1] <- "Grouping Variable"
label[2] <- "Response Variable"
mylabels <- data.frame(label)
row.names(mylabels) <- vname

# variable label as the title of a graph from a standard R function
# the data are not attached, so identify using the with function
with(mydata, barplot(table(X), main=label(X)))
with(mydata, hist(Y, main=label(Y)))