DDIwR (version 0.18)

getMetadata: Extract metadata information

Description

Extract a list containing the variable labels, value labels and any available information about missing values.

Usage

getMetadata(x, encoding = "UTF-8", ignore = NULL, ...)

Value

An R list roughly equivalent to a DDI Codebook, containing all variables, their corresponding variable labels and value labels, and (if applicable) missing values if imported and found.

Arguments

x

A path to a file, or a data frame object

encoding

The character encoding used to read a file

ignore

Character, ignore DDI elements when reading from an XML file

...

Additional arguments for this function (internal use only)

Author

Adrian Dusa

Details

This function extracts the metadata from an R dataset, or alternatively it can read an XML file containing a DDI codebook version 2.6, or an SPSS or Stata file and returns a list containing the variable labels, value labels and information about the missing values.

If the input is a dataset, it will extract the variable level metadata (labels, missing values etc.). From a DDI XML file, it will import all metadata elements, the most expensive being the data description.

For the moment, only DDI Codebook is supported, but DDI Lifecycle is planned to be implemented.

Examples

x <- data.frame(
    A = declared(
        c(1:5, -92),
        labels = c(Good = 1, Bad = 5, NR = -92),
        na_values = -92
    ),
    C = declared(
        c(1, -91, 3:5, -92),
        labels = c(DK = -91, NR = -92),
        na_values = c(-91, -92)
    )
)

getMetadata(x)