[R] scales percent precision

[Jacob Wegelin]

Incidentally,

?scales::percent

brings up exactly the same text as

?scales::percent_format

On 2014-02-27 Thu 14:47, Jacob Wegelin wrote:
> But percent_format() does not take the argument, multiply it by 100, and 
> paste on a percent sign, as we see here:
>
>> ?scales::percent_format
>> percent_format(0.0101010101)
> Error in percent_format(0.0101010101) : unused argument(s) (0.0101010101)
>> args(percent_format)
> function () NULL
>
> And how do we control the significant digits when we use percent()?
>
>> percent(0.0101010101)
> [1] "1.01%"
>
> My point is that
>
>> ?scales::percent_format
>
> does not answer these questions. This is what I mean by saying that the 
> function is not documented.
>
> On 2014-02-27 Thu 14:34, Dennis Murphy wrote:
>> Hi:
>> 
>> On Thu, Feb 27, 2014 at 8:49 AM, Jacob Wegelin <jacobwegelin at fastmail.fm> 
>> wrote:
>>> 
>>> scales::percent appears not to be documented.
>> 
>> ?scales::percent_format
>> 
>> where it tells you that it takes its argument, multiplies it by 100
>> and then attaches a percent sign to it. For most situations, the data
>> should be relative frequencies/proportions. BTW, many of the functions
>> in the scales package are second-order R functions, which means there
>> are two calls in the function invocation. The first call returns a
>> function and the second is a call to the returned function.
>> 
>>> 
>>> Details:
>>> 
>>> At http://cran.r-project.org/web/packages/scales/scales.pdf, equivalently 
>>> in
>>> ?percent, I find no answer to the following two questions.
>>> 
>>> (1) How can I specify the number of decimal points in a call to percent()?
>>> For instance, 0.010101 could be
>>> 
>>> 1%
>>> 
>>> 1.0%
>>> 
>>> 1.01%
>>> 
>>> etc. depending on what kind of report I'm writing.
>>> 
>>> I can control precision myself by writing
>>> 
>>> mypercent<-function(theargument, siglevel=2) {
>>>         stopifnot(is.numeric(theargument))
>>>         paste(signif(theargument, siglevel) * 100, "%", sep="")
>>> }
>>> 
>>> and then we have
>>> 
>>>> mypercent(0.010101)
>>> 
>>> [1] "1%"
>>>> 
>>>> mypercent(0.010101, 5)
>>> 
>>> [1] "1.0101%"
>>>> 
>>>> mypercent(0.010101, 3)
>>> 
>>> [1] "1.01%"
>> 
>> percent_format() uses pretty breaks by default, so you'd probably want
>> to pass your desired labels to scale_y_continuous() directly and avoid
>> percent_format(). You could call the function on a vector of breaks
>> and use the return values for the labels.
>> 
>>> 
>>> (2) What is the function precision() inside percent()? I find no
>>> documentation for it, and in fact it does not appear in the search path. 
>>> Nor
>>> does round_any().
>> 
>> round_any() comes from the plyr package. I have no idea where
>> precision() comes from; I've wondered about that myself a couple of
>> times. I imagine it comes from one of the imported packages, but I
>> didn't find it in any of plyr, stringr or labeling. I didn't check the
>> color-related packages (RColorBrewer, dichromat or munsell). It could
>> also be a hidden function.
>> 
>> Dennis
>>> 
>>>> percent(0.010101)
>>> 
>>> [1] "1.01%"
>>>> 
>>>> percent
>>> 
>>> function (x) {
>>>     x <- round_any(x, precision(x)/100)
>>>     str_c(comma(x * 100), "%")
>>> }
>>> <environment: 0x10c0f9350>
>>>> 
>>>> find("precision")
>>> 
>>> character(0)
>>>> 
>>>> find("round_any")
>>> 
>>> character(0)
>>>> 
>>>> 
>>> 
>>> Thanks for any insights
>>> 
>>> Jacob Wegelin
>>> 
>>>> sessionInfo()
>>> 
>>> R version 2.15.3 (2013-03-01)
>>> Platform: x86_64-apple-darwin9.8.0/x86_64 (64-bit)
>>> 
>>> locale:
>>> [1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8
>>> 
>>> attached base packages:
>>>  [1] tools     grid      splines   stats     graphics  grDevices utils
>>> datasets  methods   base
>>> 
>>> other attached packages:
>>> [1] scales_0.2.3    xtable_1.7-0    reshape2_1.2.2  moments_0.13
>>> corrplot_0.70   ggplot2_0.9.3.1 nlme_3.1-108
>>> 
>>> loaded via a namespace (and not attached):
>>>  [1] colorspace_1.2-0   dichromat_1.2-4    digest_0.6.0       gtable_0.1.2
>>> labeling_0.1       lattice_0.20-13    MASS_7.3-23        munsell_0.4
>>>  [9] plyr_1.8           proto_0.3-10       psych_1.2.8
>>> RColorBrewer_1.0-5 stringr_0.6.2
>>>> 
>>>> 
>>> 
>>> ______________________________________________
>>> R-help at r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide 
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>> 
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>