[R] (no subject)

[Marc Schwartz]

On Wed, 2004-03-17 at 16:32, Mark Van De Vyver wrote:
> Hi Marc,
> Thanks for the response.  Apologies for the lack of detail... I have used
> 'boxwex', 'at' and ylim, to place things nicely, except I know have some
> spare room at the end of the plot, which I would like to get rid of.... Your
> suggestion to use 'add' per the example is one I had not thought of.  Does
> any one know of a simpler approach, to use add I'm need to create two
> boxplots, a dummy (with x taking the correct range of values, say
> boxplot(1:10, ylim = c(0, 100))) and the real box plot with, say 11 box
> plots...
> 
> Thanks again
> Mark


Mark,

I am perhaps still a bit confused. Do you have 11 'unrelated' groups of
data or is it perhaps 5 pairs (10 total) plus one additional that is
separate and off by itself?

If it is 11 separate groups, they should space evenly across the x axis
based upon the default way boxplot() handles such things. The x axis
positions will be 1:11, with the same amount of space on the left and
right hand sides of the plot.

For example:

# Create a 11 column dataframe
x <- data.frame(matrix(rnorm(50 * 11), ncol = 11))

# Do the default boxplot
boxplot(x)



On the other hand, if you perhaps have the second scenario of 5 pairs
and a separate single, you could do something like the following:

# Create a plot window with x from 0.5 to 6.5 and y reflecting the
# range of values in 'x'
plot(c(0.5, 6.5), range(x), type = "n", ann = FALSE, axes = FALSE)

# Now add boxplots for the 'odd' columns in 'x', adding the 11th
# column. Set the 'at' values to pair up the first 5 cols and
# plot the 11th column at x = 6.2 for symmetry.
boxplot(x[, c(1, 3, 5, 7, 9, 11)], at = c(1:5 - 0.2, 6.2), 
        boxwex = 0.2, add = TRUE, xaxt = "n")

# Now add boxplots for the 'even' columns in 'x'
# Set the 'at' values to pair these up with the above
boxplot(x[, c(2, 4, 6, 8, 10)], at = 1:5 + 0.2, 
        boxwex = 0.2, add = TRUE, xaxt = "n")

Not sure if that is what you are looking for, but it might provide some
food for thought.

HTH,

Marc Schwartz