Create tab-delimited file and Mplus input syntax from R data.frame

The prepareMplusData function converts an R data.frame (or a list of data frames), into a tab-delimited file (without header) to be used in an Mplus input file. The corresponding Mplus syntax, including the data file definition and variable names, is printed to the console or optionally to an input file.

Usage

prepareMplusData(
  df,
  filename = NULL,
  inpfile = FALSE,
  keepCols = NULL,
  dropCols = NULL,
  dummyCode = NULL,
  interactive = TRUE,
  overwrite = TRUE,
  imputed = FALSE,
  writeData = c("always", "ifmissing", "never"),
  hashfilename = FALSE,
  quiet = TRUE,
  use_relative_path = FALSE
)

Arguments

df: The R data.frame to be prepared for Mplus
filename: The path and filename for the tab-delimited data file for use with Mplus. Example: "C:/Mplusdata/data1.dat"
inpfile: Logical value whether the Mplus syntax should be written to the console or to an input file. Defaults to FALSE. If TRUE, the file name will be the same as filename with the extension changed to .inp. Alternately, this can be a character string giving the file name to write the Mplus syntax to.
keepCols: A character vector specifying the variable names within df to be output to filename or a numeric vector of the column indices to be output or a logical vector corresponding to the same.
dropCols: A character vector specifying the variable names within df to be omitted from the data output to filename or a numeric vector of the column indices not to be output or a logical vector corresponding to the same.
dummyCode: An optional character vector of column names indicating categorical variables in the dataset that should be converted into dummy codes (using the fastDummies package). Note that one dummy code is returned for each level, so no reference category is implied. Thus, it is up to you to drop one of the dummy codes in the Mplus syntax to denote the reference category and avoid multicollinearity.
interactive: Logical value indicating whether file names should be selected interactively. If filename is missing and interative=TRUE, then a dialogue box will pop up to select a file or a console prompt if in a non interactive context. Defaults to TRUE.
overwrite: Logical value indicating whether data and input (if present) files should be overwritten. Defaults to TRUE to be consistent with prior behavior. If FALSE and the file to write the data to already exists, it will throw an error.
imputed: A logical whether data are multiply imputed. Defaults to FALSE. If TRUE, the data should be a list, where each element of the list is a multiply imputed dataset.
writeData: A character vector, one of ‘always’, ‘ifmissing’, ‘never’ indicating whether the data files (*.dat) should be written to disk. Defaults to ‘always’ for consistency with previous behavior. See details for further information.
hashfilename: A logical whether or not to add a hash of the raw data to the data file name. Defaults to FALSE for consistency with previous behavior where this feature was not available.
quiet: optional. If TRUE, show status messages in the console.
use_relative_path: If TRUE, only include the relative path in the DATA: FILE = syntax returned by the function. This works well if the .dat file and the .inp file are located in the same folder, as is common for Mplus. Default: FALSE.

Value

Invisibly returns a character vector of the Mplus input syntax. Primarily called for its side effect of creating Mplus data files and optionally input files.

Details

The writeData argument is new and can be used to reduce overhead from repeatedly writing the same data from R to the disk. When using the ‘always’ option, prepareMplusData behaves as before, always writing data from R to the disk. When ‘ifmissing’, R generates an md5 hash of the data prior to writing it out to the disk. The md5 hash is based on: (1) the dimensions of the dataset, (2) the variable names, (3) the class of every variable, and (4) the raw data from the first and last rows. This combination ensures that under most all circumstances, if the data changes, the hash will change. The hash is appended to the specified data file name (which is controlled by the logical hashfilename argument). Next R checks in the directory where the data would normally be written. If a data file exists in that directory that matches the hash generated from the data, R will use that existing data file instead of writing out the data again. A final option is ‘never’. If this option is used, R will not write the data out even if no file matching the hash is found.

Author

Michael Hallquist

Examples

if (FALSE) { # \dontrun{
library(foreign)

study5 <- read.spss("reanalysis-study-5-mt-fall-08.sav", to.data.frame=TRUE)
ASData5 <- subset(study5, select=c("ppnum", paste("as", 1:33, sep="")))

prepareMplusData(ASData5, "study5.dat")


# basic example
test01 <- prepareMplusData(mtcars, "test01.dat")



# see that syntax was stored
test01

# example when there is a factor and logical
tmpd <- mtcars
tmpd$cyl <- factor(tmpd$cyl)
tmpd$am <- as.logical(tmpd$am)
prepareMplusData(tmpd, "test_type.dat")
rm(tmpd)

# by default, if re-run, data is re-written, with a note
test01b <- prepareMplusData(mtcars, "test01.dat")

# if we turn on hashing in the filename the first time,
# we can avoid overwriting notes the second time
test01c <- prepareMplusData(mtcars, "test01c.dat", hashfilename=TRUE)

# now that the filename was hashed in test01c, future calls do not re-write data
# as long as the hash matches
test01d <- prepareMplusData(mtcars, "test01c.dat",
  writeData = "ifmissing", hashfilename=TRUE)

# now that the filename was hashed in test01c, future calls do not re-write data
# as long as the hash matches
test01db <- prepareMplusData(mtcars, "test01d.dat",
  writeData = "ifmissing", hashfilename=TRUE)

# however, if the data change, then the file is re-written
test01e <- prepareMplusData(iris, "test01c.dat",
  writeData = "ifmissing", hashfilename=TRUE)

# tests for keeping and dropping variables
prepareMplusData(mtcars, "test02.dat", keepCols = c("mpg", "hp"))
prepareMplusData(mtcars, "test03.dat", keepCols = c(1, 2))
prepareMplusData(mtcars, "test04.dat",
  keepCols = c(TRUE, FALSE, FALSE, TRUE, FALSE,
  FALSE, FALSE, FALSE, FALSE, FALSE, FALSE))

prepareMplusData(mtcars, "test05.dat", dropCols = c("mpg", "hp"))
prepareMplusData(mtcars, "test06.dat", dropCols = c(1, 2))
prepareMplusData(mtcars, "test07.dat",
  dropCols = c(TRUE, FALSE, FALSE, TRUE, FALSE,
  FALSE, FALSE, FALSE, FALSE, FALSE, FALSE))


# interactive (test08.dat)
prepareMplusData(mtcars, interactive=TRUE)

# write syntax to input file, not stdout
prepareMplusData(mtcars, "test09.dat", inpfile=TRUE)

# write syntax to alternate input file, not stdout
prepareMplusData(mtcars, "test10.dat", inpfile="test10alt.inp")

# should be error, no file
prepareMplusData(mtcars, interactive=FALSE)

# new warnings if it is going to overwrite files
# (the default to be consistent with prior behavior)
prepareMplusData(mtcars, "test10.dat")

# new warnings if it is going to overwrite files
# (the default to be consistent with prior behavior)
prepareMplusData(mtcars, "test11.dat", inpfile="test10alt.inp")

# new errors if files exist and overwrite=FALSE
prepareMplusData(mtcars, "test10.dat",
  inpfile="test10alt.inp", overwrite=FALSE)


# can write multiply imputed data too
# here are three "imputed" datasets
idat <- list(
  data.frame(mpg = mtcars$mpg, hp = c(100, mtcars$hp[-1])),
  data.frame(mpg = mtcars$mpg, hp = c(110, mtcars$hp[-1])),
  data.frame(mpg = mtcars$mpg, hp = c(120, mtcars$hp[-1])))

# if we turn on hashing in the filename the first time,
# we can avoid overwriting notes the second time
testimp1 <- prepareMplusData(idat, "testi1.dat",
  writeData = "ifmissing", hashfilename=TRUE,
  imputed = TRUE)

# now that the filename was hashed, future calls do not re-write data
# as long as all the hashes match
testimp2 <- prepareMplusData(idat, "testi2.dat",
  writeData = "ifmissing", hashfilename=TRUE,
  imputed = TRUE)

# in fact, the number of imputations can decrease
# and they still will not be re-written
testimp3 <- prepareMplusData(idat[-3], "testi3.dat",
  writeData = "ifmissing", hashfilename=TRUE,
  imputed = TRUE)

# however, if the data changes, then all are re-written
# note that it warns for the two files that already exist
# as these two are overwritten

idat2 <- list(
  data.frame(mpg = mtcars$mpg, hp = c(100, mtcars$hp[-1])),
  data.frame(mpg = mtcars$mpg, hp = c(109, mtcars$hp[-1])),
  data.frame(mpg = mtcars$mpg, hp = c(120, mtcars$hp[-1])))
testimp4 <- prepareMplusData(idat2, "testi4.dat",
  writeData = "ifmissing", hashfilename=TRUE,
  imputed = TRUE)


} # }