mmparker

# Calculate age at a given reference date
# Create an interval between the date of birth and the enrollment date; 
# intervals are specific to the two dates. Periods give the actual length
# of time between those dates, so convert to period and extract the year.

calc_age <- function(birthDate, refDate = Sys.Date(), unit = "year") {
    
    require(lubridate)
    

jeromyanglim

This post examines the features of [R Markdown](http://www.rstudio.org/docs/authoring/using_markdown) 
using [knitr](http://yihui.name/knitr/) in Rstudio 0.96.
This combination of tools provides an exciting improvement in usability for 
[reproducible analysis](http://stats.stackexchange.com/a/15006/183).
Specifically, this post 
(1) discusses getting started with R Markdown and `knitr` in  Rstudio 0.96;
(2) provides a basic example of producing console output and plots using R Markdown;
(3) highlights several code chunk options such as caching and controlling how input and output is displayed;
(4) demonstrates use of standard Markdown notation as well as the extended features of formulas and tables; and 
(5) discusses the implications of R Markdown.