This support has been added (at least in roxygen2).  You just need to add `@section Llamas:` and then anything after that until a new directive is met will be in a Llamas section.  Here is an example

    #&#39; Llama llama llama
    #&#39; 
    #&#39; More about llamas
    #&#39; 
    #&#39; @section Llamas:
    #&#39; Are they ungulates?
    #&#39; 
    #&#39; @section Not llamas:
    #&#39; This section is not about llamas.  It is not very interesting.
    #&#39; 
    #&#39; @param notused A parameter that isn&#39;t used at all!
    #&#39; @export
    llama &lt;- function(notused){
        return(&quot;LLAMA LLAMA LLAMA&quot;)
    }

which gives the following for the .Rd file



    \name{llama}
    \alias{llama}
    \title{Llama llama llama}
    \usage{
      llama(notused)
    }
    \arguments{
      \item{notused}{A parameter that isn&#39;t used at all!}
    }
    \description{
      More about llamas
    }
    \section{Llamas}{
      Are they ungulates?
    }
    
    \section{Not llamas}{
      This section is not about llamas.  It is not very
      interesting.
    }



how can I convert a string ipAddress (struct in_addr) and vice versa?
and how do I turn in unsigned long ipAddress?
thanks

How to convert string to IP address and vice versa

I&#39;ve seen docs/websites show that custom validators should go in a `/lib` or `/lib/validators` directory of a project. I&#39;ve found (by reading an answer to another post) that they only seem to work in `config/initializers`. Does anyone know, or have a pointer to official documentation that shows where custom validators should live?


Where should Rails 3 custom validators be stored?

The way [Roxygen][1] seems to work is that the first line is the `\title`, everything else is in the `\details`, and then any `@foo` directives handle those things. But R documentation is richer than that. I can have `&quot;\section{Llamas}{Are they ungulates?}&quot;` in .Rd files.

But I can&#39;t get Roxygen to do anything other than wrap it all in \details. Am I missing something?

I have a hacky solution, which is to stick an unmatched `}` before my `\section`. This then ends the `\details` section. I then have to not put an ending `}` in, because roxygen sticks one in thinking its closing the `\details`. Eeeeeurrrrrrrrgh.


  [1]: http://roxygen.org/

Arbitrary sections in roxygen docs

The way <a href="http://roxygen.org/" target="_blank" rel="noopener noreferrer">Roxygen</a> seems to work is that the first line is the <code>\title</code>, everything else is in the <code>\details</code>, and then any <code>@foo</code> directives handle those things. But R documentation is richer than that. I can have <code>"\section{Llamas}{Are they ungulates?}"</code> in .Rd files.
But I can't get Roxygen to do anything other than wrap it all in \details. Am I missing something?
I have a hacky solution, which is to stick an unmatched <code>}</code> before my <code>\section</code>. This then ends the <code>\details</code> section. I then have to not put an ending <code>}</code> in, because roxygen sticks one in thinking its closing the <code>\details</code>. Eeeeeurrrrrrrrgh.

I have a graph of wind speeds against direction which has a huge numeber of points, and so am using alpha=I(1/20) in addition to color=month

Here is a sample of code:

    library(RMySQL)
	library(ggplot2)
	con &lt;- dbConnect(...)
	wind &lt;- dbGetQuery(con, &quot;SELECT speed_w/speed_e AS ratio, dir_58 as dir, MONTHNAME(timestamp) AS month, ROUND((speed_w+speed_e)/2) AS speed FROM tablename;&quot;);

	png(&quot;ratio-by-speed.png&quot;,height=400,width=1200)
	qplot(wind$dir,wind$ratio,ylim=c(0.5,1.5),xlim=c(0,360),color=wind$month,alpha=I(1/30),main=&quot;West/East against direction&quot;)
	dev.off()


This produces a decent graph, however my issue is that the alpha of the legend is 1/30th also, which makes it unreadable. Is there a way I can force the legend to be 1 alpha instead?

Here is an example:
![Example Graph][1]


  [1]: http://i.stack.imgur.com/Y1dWv.png

How to set legend alpha with ggplot2

My categories need to be named with Greek letters.  I am using `ggplot2`, and it works beautifully with the data.  Unfortunately I cannot figure out how to put those greek symbols on the x axis (at the tick marks) and also make them appear in the legend.  Is there any way to do it?

UPDATE:
I had a look at the [link](https://github.com/hadley/ggplot2/wiki/Axis-Attributes), however, there is no good method described to accomplish what I want to do.  

How to use Greek symbols in ggplot2?

I&#39;m starting to use the great `ggplot2` package for plotting in R, and one of the first things I ask myself before each plot is *&quot;well, will I use `qplot` or `ggplot` ?&quot;*

I understand that `qplot` provides a simpler syntax while `ggplot` allows maximum features and flexibility, but what is the function you use the most, and do you have some precise use cases for each one ? Do you use mostly `qplot` and `ggplot` only for complex plots, or do you use `ggplot` everytime ?

Thanks for your feedback !

Choosing between qplot() and ggplot() in ggplot2

I have a dataframe with a column of p-values and I want to make a selection on these p-values. 

    &gt; pvalues_anova
    [1] 9.693919e-01 9.781728e-01 9.918415e-01 9.716883e-01 1.667183e-02
    [6] 9.952762e-02 5.386854e-01 9.997699e-01 8.714044e-01 7.211856e-01
    [11] 9.536330e-01 9.239667e-01 9.645590e-01 9.478572e-01 6.243775e-01
    [16] 5.608563e-01 1.371190e-04 9.601970e-01 9.988648e-01 9.698365e-01
    [21] 2.795891e-06 1.290176e-01 7.125751e-01 5.193604e-01 4.835312e-04

Selection way:

    anovatest&lt;- results[ - which(results$pvalues_anova &lt; 0.8) ,]

The function works really fine if I use it in R. But if I run it in another application (galaxy), the numbers which don&#39;t have `e-01` e.g. `4.835312e-04` are not thrown out.

Is there another way to notate p-values, like `0.0004835312` instead of `4.835312e-04`?


How to disable scientific notation?

Even though I found Hadley&#39;s post in the google group on `POSIXct` and `geom_vline`, I could not get it done. I have a time series from and would like to draw a vertical line for years 1998, 2005 and 2010 for example. I tried with `ggplot` and `qplot` syntax, but still I either see no vertical line at all or the vertical line is drawn at the very first vertical grid and the whole series is shifted somewhat strangely to the right.

    gg &lt;- ggplot(data=mydata,aes(y=somevalues,x=datefield,color=category)) +
          layer(geom=&quot;line&quot;)
    gg + geom_vline(xintercept=mydata$datefield[120],linetype=4)
    # returns just the time series plot I had before, 
    # interestingly the legend contains dotted vertical lines

My date field has format &quot;1993-07-01&quot; and is of class `Date`.

How to get a vertical geom_vline to an x-axis of class date?

I&#39;ve read the Roxygen2 PDF and this [site][1], and I&#39;m lost on the difference between @method @S3method @export and how to use these to properly document S3 methods. I worked up the follow example for discussion:&lt;br/&gt;&lt;br/&gt;
1. How would I properly document these?&lt;br/&gt;&lt;br/&gt;
2. How do I emulate documentation of ?print and other generic functions that show the use cases for all class-specific implimentations (i.e. the way ?print shows usage for &#39;factor&#39;, &#39;table&#39;,&#39;function&#39;)&lt;br/&gt;&lt;br/&gt;
3. From the wiki page: &quot;All exported methods need the @S3method tag. It has the same format as @method. This exports the method, not the function - i.e. generic(myobject) will work, but generic.mymethod(myobject) will not.&quot;&lt;br/&gt;
I can&#39;t interpret this.  This seems to say that function/method calls won&#39;t work properly if the tags are improperly specified?  What specifically will break?

    MyHappyFunction = function( x , ... )
    {
        UseMethod( &quot;MyHappyFunction&quot; )
    }
    
    MyHappyFunction.lm = function( x , ... )
    {
      # do some magic
    }


  [1]: https://github.com/hadley/devtools/wiki/docs-function


Roxygen2 - how to properly document S3 methods

What is the appropriate syntax to add an itemized list to roxygen2, for instance, in the @details section?  Can I create a latex list environment?

It seems that line breaks are simply ignored, i.e. 

    #&#39; @details text describing parameter inputs in more detail
    #&#39;
    #&#39; parameter 1: stuff
    #&#39; 
    #&#39; parameter 2: stuff

thanks!

When documenting in Roxygen: How do I make an itemized list in @details?

**Short version**: Can I emulate the documentation of `Normal` in package `stats` using `roxygen`?

**Long version**: I&#39;m working on a package and was trying make the documentation more readable by having a number of functions with common inputs/parameters collected under one heading, which will be a generic reference to the group. Each function should still be available to the end user independently. 

I took as inspiration the documentation for `Normal` which gives a number of methods related to the normal distribution e.g. `stats::dnorm()`. 

When I search `?dnorm` I find the name of the help section is `Normal` even though `Normal` does not appear to be an exported function or object.

What I&#39;ve tried is putting the following into `funs.R`:

    ##&#39; @rdname funs
    ##&#39; @name funs
    ##&#39; @aliases sum1
    ##&#39; @aliases prod1
    ##&#39; @title Two functions
    ##&#39; @param x X
    ##&#39; @param y Y
    ##&#39; @return sum1 returns x+y
    ##&#39; \cr
    ##&#39; prod1 returns x*y
    ##&#39; @examples
    ##&#39; sum1(3,4)
    ##&#39; prod1(3,4)
    ##&#39; @export
    sum1 &lt;- function(x,y) x+y
    ##&#39; @export
    ##&#39; @rdname funs
    prod1 &lt;- function(x,y) x*y

I then run `roxygen2` on the above.
The difficulty is that when running `R CMD check` on this minimal package, it finds the package cannot be loaded as `undefined exports: funs`. 
If I remove the line `##&#39; @name funs` the package passes `R CMD check` but the name of the help section is `sum1` rather than `funs`.
If I add the following below the examples section:

    ##&#39; @export
    funs &lt;- function(x) x

It passes and I can see the help formatted as I would like, but I&#39;m exporting a meaningless function in order to get the name to display correctly. 

I tried looking in the source help files for `stats` to see how it was achieved, but they are in `.Rdx` format which I&#39;m not sure how to display. 

Also, on a related note, does what sort of thing *is* `Normal`?

    require(stats)
    getAnywhere(&quot;Normal&quot;)
    &gt; no object named &#39;Normal&#39; was found

---------
**Update:**

@TylerRinker - I&#39;m afraid this was the first thing I had tried. This combines the functions into one `.Rd` file but the name of the associated help is the same as the name of the first function, which is what I was trying to avoid:

    ##&#39; sum
    ##&#39; gives the sum
    ##&#39; @param x X
    ##&#39; @param y Y
    ##&#39; @return sum1 returns x+y
    ##&#39; @examples
    ##&#39; sum1(3,4)
    ##&#39; @rdname funs
    ##&#39; @export
    sum1 &lt;- function(x,y) x+y
    ##&#39; product
    ##&#39; gives the product
    ##&#39; @return prod1 returns x*y
    ##&#39; @examples
    ##&#39; prod1(3,4)
    ##&#39; @rdname funs
    ##&#39; @export
    prod1 &lt;- function(x,y) x*y

@Andrie - this solution causes exactly the same difficulty, the name of the help is the same as the first function.

Perhaps this just isn&#39;t possible... 




Content Type	Original Author	Original Content on Stackoverflow
Question	Spacedman	View Question on Stackoverflow
Solution 1 - R	Dason	View Answer on Stackoverflow

Arbitrary sections in roxygen docs

R Problem Overview

R Solutions

Solution 1 - R

Where should Rails 3 custom validators be stored?

How to convert string to IP address and vice versa

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