I have constructed a Trellis style xyplot.

lengthf <- factor(length)
xyplot(SLI$velocity ~ SLI$width | SLI$lengthf, layout = c(2,7), xlab =
"Width (cm)", ylab = "Velocity (m/s^2)", col = "black")

This produces a lovely little plot. However, the grouping factor(lengthf)
isn't in the right order. My values range from 2-28 and the 2 graph on the
bottom left and the graphs continue sequentially left to right to the top of
the page. I would like to have the 2 at the top and have the graphs shown in
descending order (i.e. have the entire graph read like a book)

I tried the following but it didn't seem to work.

lengthd <-sort(SLI$length, decreasing =TRUE)
lengthdf <- factor(SLI$lengthd)

Then I plotted the graph again:
xyplot(SLI$velocity ~ SLI$width | SLI$lengthdf, layout = c(2,7), xlab =
"Width (cm)", ylab = "Velocity (m/s^2)", col = "black")

This simply gave me the same graph and now I am a little lost. Is there an
easier way to do this? Do I have to rearrange my data or can this be changed
around using the original xyplot command line. Thanks.

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