barpercent.R

# draws a horizontal bar chart with percentages labeled
barpercent <- function (x, names = NULL, col = "lightblue") {
    if (is.null(names)) names <- names(x)
    par (las = 1, mar = c(5,10,4,6), xpd = NA, xaxs = "i", yaxs= "i")
    data <- x[order(x)]*100/sum(x)
    labels <- paste(names[order(x)],"   ",
                    formatC(data,digits=1,format="f",width=4))
    xmax <- round(max(data),digits = -1)
    ymax <- (length(x)*1.2)+.1
    plot(NULL, xlim = c(0,xmax), ylim=c(0,ymax), axes = FALSE,
         xlab = "percent", ylab="")
    barplot(data, horiz = TRUE, names.arg = labels,
            col = col, border = col,
            axes = FALSE, add = TRUE)
    axis (1, pos = 0, xlim = c(0,xmax), at = c(0,1:(xmax/10)*10))
    hat <- -xmax/16.66667
    text(hat, .2, "100.0", adj = c(1,1))
    text(hat, .2, "%", adj = c(0,1))
    lines(c(.3,3.2)*hat,c(.25,.25))
}

# examples
# barpercent(c(4,23, 45), c("Region 1","Region 2","Region 3"))

# x <- c(4, 23, 45)
# names(x) <- c("Region 1","Region 2","Region 3")
# barpercent (x)
# barpercent (x, col = "rosybrown1")