[R] Setting breaks for histogram of dates

[Loris Bennett]

Loris Bennett <loris.bennett at fu-berlin.de> writes:

> Hi,
>
> I have a list of dates like this: 
>
>   date
>   2009-12-03
>   2009-12-11
>   2009-10-07
>   2010-01-25
>   2010-01-05
>   2009-09-09
>   2010-01-19
>   2010-01-25
>   2009-02-05
>   2010-01-25
>   2010-01-27
>   2010-01-27
>   ...
>
> and am creating a histogram like this
>
>   t <- read.table("test.dat",header=TRUE)
>   hist(as.Date(t$date), "years", format = "%d/%m/%y", freq=TRUE)
>   
> However, I would rather not label the breaks themselves, but instead
> print the date with the format "%Y", between the breaks.
>
> Is there a simple way of doing this?
>
> Regards
>
> Loris
>
> -- 
> Dr. Loris Bennett
> ZEDAT Computer Centre
> Freie Universität Berlin
> Berlin, Germany
>
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> and provide commented, minimal, self-contained, reproducible code.

With a little help from a chap called Jim who doesn't seem to have
replied to the list, I looked discovered 'axis' and came up with
this:

  > hist(as.Date(t$date),"years",format="%Y",freq=TRUE,xaxt="n")
  In hist.default(unclass(x), unclass(breaks), plot = FALSE, ...) :
    argument '...' is not made use of
  > axis(1,at=as.Date(c("2009-07-01","2010-07-01")),
      labels=c("2009","2010"),lwd=0,lwd.ticks=0)

I don't know what to make of the warning but the labels are placed as
I want.

Loris

-- 
Dr. Loris Bennett
ZEDAT Computer Centre
Freie Universität Berlin
Berlin, Germany