You can use the which.i argument to [.xts:

> is.null(SPY["2009-01-18",which.i=TRUE])
[1] TRUE

Best,
--
Joshua Ulrich  |  about.me/joshuaulrich
FOSS Trading  |  www.fosstrading.com


On Sat, Jan 25, 2014 at 9:27 AM, ce <zadig_1@excite.com> wrote:

> Dear all
>
>
> How to test if xts date exists ? is.null doesn't work.  SPY["2009-01-18"]
> doesn't exist but I can't catch it in my script.
>
> library(quantmod)
>
> getSymbols("SPY")
>
> > SPY["2009-01-16"]
>            SPY.Open SPY.High SPY.Low SPY.Close SPY.Volume SPY.Adjusted
> 2009-01-16    85.86    85.99   83.05     85.06  399237200        76.58
>
>
>
> > SPY["2009-01-18"]
>      SPY.Open SPY.High SPY.Low SPY.Close SPY.Volume SPY.Adjusted
>
>
> > is.null(SPY["2009-01-18"])
> [1] FALSE
>
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> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

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