quantmod's addTA plotting functions

Thanks. You're right. I didn't see that.  I read the ?addTA help page,
which (annoyingly) didn't mention that feature, but I didn't read the
?TA page. (That page was mentioned as a see also, but not as a must see.)

I don't know what it means to wrap these calls in a plot call. I tried
to put the addTA calls into a function and call that function from the
higher level function, but that didn't work either. Would you tell me
what it means to wrap these calls in a plot call.

Thanks
/-- Russ /

P.S. Pardon my irritation, but I continually find that many of the help
files assume one already knows the information one is looking for. If
you don't know it, the help files are not very helpful.  This is a good
example.  In fact, it's two good examples.  I didn't know that I had to
look at another page, and I (still) don't know what it means to wrap
plot calls in another plot call.


On Thu, May 5, 2011 at 3:39 AM, P Ehlers <ehlers at ucalgary.ca
<mailto:ehlers at ucalgary.ca>> wrote:

    On 2011-05-05 0:47, Russ Abbott wrote:

        Hi,

        I'm having trouble with quantmod's addTA plotting functions.
          They seem to
        work fine when run from the command line. But when run inside a
        function,
        only the last one run is visible.  Here's an example.


        test.addTA<- function(from = "2010-06-01") {
             getSymbols("^GSPC", from = from)
             GSPC.close<- GSPC[,"GSPC.Close"]
             GSPC.EMA.3<- EMA(GSPC.close, n=3, ratio=NULL)
             GSPC.EMA.10<- EMA(GSPC.close, n=10, ratio=NULL)
             chartSeries(GSPC.close, theme=chartTheme('white'),
        up.col="black",
        dn.col="black")
             addTA(GSPC.EMA.3,   on = 1, col = "#0000ff")
             addTA(GSPC.EMA.10,  on = 1, col = "#ff0000")
             # browser()
        }


        When I run this, GSPC.close always appears.  But only GSPC.EMA10
        appears on
        the plot along with it. If I switch the order of the addTA calls,
        only GSPC.EMA3 appears. If I uncomment the call to browser()
        neither appears
        when the browser() interrupt occurs. I can then draw both
        GSPC.EMA.3 and
        GSPC.EMA10 manually, and let the function terminate. All
        intended plots are
        visible after the function terminates. So it isn't as if one
        wipes out the
        other. This shows that it's possible to get all three lines on
        the plot, but
        I can't figure out how to do it without manual intervention. Any
        suggestions
        are appreciated.


    Perhaps you didn't see this NOTE on the ?TA help page:

    "Calling any of the above methods from within a function
    or script will generally require them to be wrapped in a
    plot call as they rely on the context of the call to
    initiate the actual charting addition."

    Peter Ehlers


        Thanks.

        *-- Russ *

                [[alternative HTML version deleted]]