# get.segs: Calculate the midpoints and limits for a centipede plot

## Description

Calculates midpoints and limits for a list or data frame for use with
centipede.plot.

## Usage

get.segs(x,mct="mean",lower.limit="std.error",upper.limit=lower.limit)

## Value

A matrix with four rows and as many columns as were in the object

`x`. The first row contains the midpoint values, the second and third
the lower and upper limit values respectively and the fourth row the number
of valid observations in the columns.

## Arguments

- x
a list or data frame.

- mct
The name of the function to calculate midpoints.

- lower.limit,upper.limit
The names of the function(s) to calculate
lower and upper limits.

## Details

`get.segs` calls the functions whose names are passed to calculate
midpoints and limits for each list element or data frame column. The
user can define special functions for the central and dispersion measures
if desired.