[R] Using boxplot in a daily time series

[Dylan Beaudette]

On Saturday 15 December 2007 07:13:34 am pedrosmarques at portugalmail.pt wrote:
> Hi all,
>
> I'm trying to plot my daily time series, with 3650 observations( 10 years),
> with boxplot but I want 12 boxes, one for each month, can anyone help me
> doing that.
>
> Best regards
>

Sure,

there are several approaches to this, but in general thinking about your data 
in terms of 'grouping' factors can be helpful

example:

# 1 year's worth of dates:
d <- strptime(1:365, format="%j")

# some simulated data
x <- rlnorm(365)

# combine them into a DF 
dx <- data.frame(date=d, value=x)

# plot the data, note that x-axis is in dates:
plot(dx)

# now generate a grouping factor. how about months:
dx$month <- format(dx$date, format="%B")

# box and whisker plot for data *grouped* by month
boxplot(value ~ month, data=dx, las=3)


cheers,

Dylan