R ggplot and facet grid: how to control x-axis breaks

Question

I am trying to plot the change in a time series for each calendar year using ggplot and I am having problems with the fine control of the x-axis. If I do not use scale

Answer 1

here is an example:

df <- transform(df, doy = as.Date(paste(2000, month, day, sep="/")))

p <- ggplot(df, aes(doy, pctchg)) +
 geom_line( aes(group = 1, colour = pctchg),size=0.75) + 
 facet_wrap( ~ year, ncol = 2) +
 scale_x_date(format = "%b") +
 scale_y_continuous(formatter = "percent") +
 opts(legend.position = "none")
p

Do you want this one?

The trick is to generate day of year of a same dummy year.

UPDATED

here is an example for the dev version (i.e., ggplot2 0.9)

p <- ggplot(df, aes(doy, pctchg)) +
  geom_line( aes(group = 1, colour = pctchg), size=0.75) + 
  facet_wrap( ~ year, ncol = 2) +
  scale_x_date(label = date_format("%b"), breaks = seq(min(df$doy), max(df$doy), "month")) +
  scale_y_continuous(label = percent_format()) +
  opts(legend.position = "none")
p