[R] Quantmod - modify decimal places

[Joshua Ulrich]

On Mon, May 23, 2016 at 8:57 PM, David Menezes
<david.n.menezes at gmail.com> wrote:
> Hi
>
> Apologies if this has already been asked and answered or if I've labelled
> the subject incorrectly but I can't find a solution using the search
> function for this group; the vignette documentation for quantmod or general
> google searches.
>
> I'm attempting to use quantmod to download foreign currency exchange
> rates.  I'm using the call "getFX" however the output results are always
> restricted to 4 decimal places.  Generally this is fine but when comparing
> developing and mature economies this can lead to no answer being returned
> due to how weak a specific currency is (in relative terms).
>
> For example, compare the following two results for converting USD to
> Vietnamese Dong (VND):
>
> a)      *1/getFX("USD/VND",from="2016-05-22",to ="2016-05-22", source =
> "oanda", auto.assign=FALSE)*
>
>  This yields…
>
>                 USD.VND
>
> 2016-05-22 4.473272e-05
>
>  However my preferred call would be:
>
>  b)*      getFX("VND/USD",from="2016-05-22",to ="2016-05-22", source =
> "oanda", auto.assign=FALSE)*
>
>  However this yields a zero result:
>
> VND.USD
>
> 2016-05-22       0
>
>
> which is clearly wrong.
>
That's the data Oanda provides via the URL quantmod::getSymbols.oanda
uses. Look for yourself:

http://www.oanda.com/currency/historical-rates/download?quote_currency=VND&end_date=2016-05-22&start_date=2016-05-22&period=daily&display=absolute&rate=0&data_range=d7&price=mid&view=table&base_currency_0=USD&base_currency_1=&base_currency_2=&base_currency_3=&base_currency_4=&download=csv

>
> I've tried various things including trying to invoke options (digits = 10)
> at the start of the script, and even within the getFX wrapper as an extra
> argument, but it doesn't work.  I can of course run select cross currency
> rates and invert the results, but that is pretty awkward and it feels like
> there ought to be a smarter and simpler solution.
>
In case it's not clear from what I said above, there's nothing you can
do to fix this after you've retrieved the data.  You need a more
accurate data source.

> Any help greatly appreciated.
>
> Thanks
> Dave
>
>         [[alternative HTML version deleted]]
>
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-- 
Joshua Ulrich  |  about.me/joshuaulrich
FOSS Trading  |  www.fosstrading.com
R/Finance 2016 | www.rinfinance.com