R/DictionarySPSS.R

In ajhmohr/datadictionary: Create TXT Data Dictionary from R Data Attributes

#' A SPSS Data Dictionary Function
#'
#' This function creates a .txt data dictionary from an SPSS .sav file read into R using the foreign package. It writes the variable labels and value labels stored as attributes within the R data object to an external file. PLEASE USE DataDictionary() for SPSS data read in using the haven package. 
#' @param x A dataframe read in using the "read.spss()" command from the foreign package. Must have "to.data.frame=TRUE" and works best if "use.value.labels=FALSE"
#' @param file The file name and location to which the data dictionary should be written. Defaults to "DataDictionary.txt" in the current working directory. 
#' @keywords data dictionary
#' @keywords metadata
#' @export
#' @examples
#' DictionarySPSS()



DictionarySPSS <- function(x, file="DataDictionary.txt") {
  
  #first, create an empty attribute called "value.labels" (as a list) and assign it to data
  attr(x, "value.labels") = list()
  #then, loop through each variable in data and copy the variable-level attribute 
  #"value.labels" to the newly created data-level attribute "value.labels", setting the 
  #new attribute equal to a blank ("") if the variable-level attribute is null. 
  for (i in 1:ncol(x)){
    if(is.null(attr(x[,i], "value.labels"))==FALSE) {
      attr(x, "value.labels")[[i]] <- attr(x[,i], "value.labels")}
    else {attr(x, "value.labels")[[i]] <- ""}}

  #set up a datatable of the variable names and labels
  value_labels <- attr(x, "value.labels")
  variable_labels <- attr(x, "variable.labels")
  datatable <- as.data.frame(variable_labels)
  
  #initialize an empty tab-separated textfile to write the metadata to
  cat("\n", file=file, sep="\t")
  
  #loop through each variable in mydata and print the variable name, variable labels,
  #and value labels (if not blank) in the text file. 
  for (i in 1:ncol(x)){
    if (value_labels[i] != "") {
      #write a line with the variable name tab-separated from the variable label
      cat(names(x)[i], "\t", paste(datatable[i,]), file=file, append=TRUE)
      #create a temporary object that combines the value label numbers with the 
      #value labels, with "=" in the middle of the two - each row contains a value label
      a <- paste(cbind(rev(value_labels[[i]]))[,1], "=", row.names(cbind(rev(value_labels[[i]]))))
      #start a new line in the text file
      cat("\n", file=file, append=TRUE)
      #now, loop through each of the rows in "a" (each individual value label) and 
      #write it in a new indented line in the text file
      for (j in 1:length(a)){
        cat("\t", a[j], "\n", file=file, append=TRUE)
      }
      #add a line to separate the next variable
      cat("\n", file=file, append=TRUE)
    }
    #if the value labels are blank, just write a new line with the variable label
    else {
      cat(names(x)[i], "\t", paste(datatable[i,]), "\n\n", file=file, append=TRUE)
    }
  }}