nhanes_load_data: Download NHANES data files.
In RNHANES: Facilitates Analysis of CDC NHANES Data

Description Usage Arguments Details Value Examples

Download NHANES data files.

nhanes_load_data(file_name, year, destination = tempdir(),
  demographics = FALSE, cache = TRUE, recode = FALSE,
  recode_data = FALSE, recode_demographics = FALSE,
  allow_duplicate_files = FALSE)

`file_name`	NHANES file name (e.g. "EPH") or a vector of filenames (e.g c("EPH", "GHB"))
`year`	NHANES cycle year (e.g. "2007-2008") or a vector of cycle years
`destination`	directory to download the files to
`demographics`	include demographics data into the dataset
`cache`	whether to cache the file to disk
`recode`	whether to recode the data and demographics (overrides other parameters)
`recode_data`	whether to recode just the data
`recode_demographics`	whether to recode just the demographics
`allow_duplicate_files`	how to handle a request that has duplicate file names/cycle years. By default duplicates will be removed.

If you supply vectors for both file_name and year, then the vectors are paired and each file_name/year pair is downloaded. For example, file_name = c("EPH, GHB"), year = c("2009-2010", "2011-2012") will download "EPH_F.XPT" and "EPH_G.XPT". In other words, the function does not download every possible combination of file_name and year.

You can specify file names in several formats. In order of specificity: You can supply the complete filename: "EPH_F.XPT" You can supply the filename without an extension: "EPH_F" You can supply the filename without a suffix: "EPH", year = "2009-2010"

If you are loading the same file across multiple years, you must supply the filename without a suffix so that the correct suffix for each year can be used.

This function returns either a list or a data frame. If you load multiple files, the return value will always be a list. This is because the columns may not match in between files. If you load one file, the result will be a data frame.

if file_name or year is a vector, returns a list containing a data frame for each file_name. If file_name and year are both singletons, then a data frame is returned.

## Not run: 

nhanes_load_data("UHG", "2011-2012")

# Load data with demographics
nhanes_load_data("UHG", "2011-2012", demographics = TRUE)

# Download to /tmp directory and overwrite the file if it already exists
nhanes_load_data("HDL_E", "2007-2008", destination = "/tmp", cache = FALSE)

## End(Not run)