nhanesAttr {nhanesA}

Returns the attributes of an NHANES data table.

Description

Returns attributes such as number of rows, columns, and memory size, but does not return the table itself.

Usage

nhanesAttr(nh_table)

Arguments

nh_table

The name of the specific table to retrieve

Details

nhanesAttr allows one to check the size and other charactersistics of a data table before importing into R. To retrieve these characteristics, the specified table is downloaded, characteristics are determined, then the table is deleted. Downloads a table from the NHANES website as is, i.e. in its entirety with no modification or cleansing. If the environment variable NHANES_TABLE_BASE was set during startup, the value of this variable is used as the base URL instead of https://wwwn.cdc.gov (this allows the use of a local or alternative mirror of the CDC data).

Value

The following attributes are returned as a list
nrow = number of rows
ncol = number of columns
names = name of each column
unique = true if all SEQN values are unique
na = number of 'NA' cells in the table
size = total size of table in bytes
types = data types of each column

Examples

bpx_e = nhanesAttr('BPX_E')
length(bpx_e)
folate_f = nhanesAttr('FOLATE_F')
length(folate_f)