R: boxplot

bplot {fields} | R Documentation

## boxplot

### Description

Plots boxplots of several groups of data and allows for placement at different horizontal or vertical positions or colors. It is also flexible in the input object, accepting either a list or matrix.

### Usage

    bplot(x, by, pos=NULL, at = pos, add = FALSE, boxwex =
                     0.8,xlim=NULL, ...)

### Arguments

`x` | Vector, matrix, list or data frame. A vector may be divided according to the by argument. Matrices and data frames are separated by columns and lists by components.
`by` | If x is a vector, an optional vector (either character or numerical) specifying the categories to divide x into separate data sets. Boxplots are then made for each group.
`pos` | The boxplots will be plotted vertically (horizontally) and pos gives the x (y) locations for their centers. If omitted the boxes are equally spaced at integer values. This is the same as `at` in the `boxplot` function
`at` | Same as `pos` this is the name for this argument in the standard `boxplot` function.
`add` | If true, do not create a new plots just add the boxplots to a current plot. Note that the pos argument may be useful in this case and should be in the user coordinates of the parent plot.
`boxwex` | A boxplot argument to control the width of the boxplot. It behaves a little different than as an argumetn passed directly to `boxplot`. To make this a general function it is useful to scale this according to size of positions. Within bplot this happens as `boxwex<- boxwex* min(diff( sort( at)))`. and then the scaled version of `boxwex` is now passed to `boxplot`.
`xlim` | Same as the usual argument used in plotting. The plotting limits for the x axis.
`...` | Other arguments to be passed to the boxplot function some handy favorites are: `names` Labels for each boxplot. `horizontal`If TRUE draw boxplots horizontally the default is false, produce vertical box plots. `lwd`Width(s) of lines in box plots. `col`Color(s) of bplots. See `colors()` for some choices.

### Details

This function was created as a complement to the usual S/R function for boxplots. The current function makes it possible to put the boxplots at unequal x or y positions in a rational way using the `at` or `pos` arguments. This is useful for visually grouping a large set of boxplots into several groups. Also placement of the boxplots with respect to the axis can add information to the plot. Another aspect is the emphasis on data structures for groups of data. One useful feature is the by option to break up the x vector into distinct groups.

Use `axis(3)` (`axis(4)`) to add an axis along the top (right side) or omit the category names and draw on the bottom `axis(1)` (left side `axis(2)`).

The older `bplot` function drew the boxplots from scratch and if one needs to do this refer to the old functions: `describe.bplot, draw.bplot.obj, bplot.xy, bplot.obj`

Finally to bin data into groups based on a continuous variable and to make bplots of each group see `bplot.xy`.

### See Also

bplot.xy

### Examples

    #
    set.seed(123)
    temp<- matrix( rnorm(12*8), ncol=12)
    pos<- c(1:6,9, 12:16)*100
    bplot(temp)
    #
    par(las=2)
    bplot( temp, pos=pos, names=paste( "Data",1:12, sep=""))
    # add an axis along top for reference
    axis(3)

    #
    # Xmas boxplots in pleasing red and green
    bplot( temp, pos=pos,  col=c("red4", "green4"))
    # add an axis on top
    axis( 3)

[Package fields version 9.6.1 Index]