Hi: Here are some possibilities using ggplot2:
library(ggplot2) # Create ordered factors bar$area2 <- ordered(bar$area) bar$year2 <- ordered(bar$year) # Side-by-side, aka dodged, bar charts ggplot(bar, aes(x = area2, y = disc, fill = year2)) + geom_bar(aes(group = year2), position = 'dodge', stat = 'identity') # Faceted bar charts (same idea as Gabor's in lattice) ggplot(bar, aes(x = year2, y = disc)) + geom_bar(fill = 'blue', stat = 'identity') + facet_wrap(~ area2) # This seems a more informative display, however: ggplot(bar, aes(x = area2, y = disc, colour = year2)) + geom_point() + geom_line(aes(group = year), size = 1) + scale_colour_discrete('Year') + xlab('Area') # A lattice version is xyplot(disc ~ area2, data = bar, groups = year, type = c('p', 'a'), lwd = 2, xlab = 'Area', key = simpleKey(corner = c(0.2, 0.45), text = levels(bar$year2), lines = TRUE, points = FALSE)) Note that corner = c(0, 1) is upper left and c(1, 0) is lower right, for example, assuming you want to change the location of the legend. HTH, Dennis On Tue, Nov 23, 2010 at 11:49 AM, Art Burke < art.bu...@educationnorthwest.org> wrote: > Given the data structure below, how can I create a bar plot for the values > of disc for each area grouped by year? > > bar <-structure(list(year = c(2003, 2003, 2003, 2003, 2003, 2003, 2003, > 2007, 2007, 2007, 2007, 2007, 2007, 2007), area = structure(c(6L, > 4L, 1L, 2L, 3L, 5L, 7L, 6L, 4L, 1L, 2L, 3L, 5L, 7L), .Label = c("AK", > "ID", "MT", "NW", "OR", "US", "WA"), class = "factor"), disc = c(55.8, > 62.6, 54.3, 56.9, 52.8, 66.7, 64.8, 59.5, 64.8, 65.8, 61.4, 60.6, > 66.3, 65.5)), .Names = c("year", "area", "disc"), class = "data.frame", > row.names = c(NA, > 14L)) > > Thanks! > Art > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.