R/mplus.lca.R

In misty: Miscellaneous Functions 'T. Yanagida'

#' Mplus Model Specification for Latent Class Analysis
#'
#' This function writes Mplus input files for conducting latent class analysis (LCA)
#' for continuous, count, ordered categorical, and unordered categorical variables.
#' LCA with continuous indicator variables are based on six different
#' variance-covariance structures, while LCA for all other variable types assume
#' local independence. By default, the function conducts LCA with continuous
#' variables and creates folders in the current working directory for each of the
#' six sets of analysis, writes Mplus input files for conducting LCA with
#' \emph{k} = 1 to \emph{k} = 6 classes into these folders, and writes the matrix
#' or data frame specified in \code{x} into a Mplus data file in the current working
#' directory. Optionally, all models can be estimated by setting the argument
#' \code{run.mplus} to \code{TRUE}.
#'
#' @param x               a matrix or data frame. Note that all variable names must
#'                        be no longer than 8 character.
#' @param ind             a character vector indicating the variables names of the
#'                        latent class indicators in \code{x}.
#' @param type            a character string indicating the variable type of the
#'                        latent class indicators, i.e., \code{"continuous"} (default)
#'                        for continuous variables, \code{"count"} for count variables,
#'                        \code{"categorical"} for binary or ordered categorical
#'                        variables, and \code{"nominal"} for unordered categorical
#'                        variables. Note that it is not possible to mix different
#'                        variable types in the analysis.
#' @param cluster         a character string indicating the cluster variable in
#'                        the matrix or data frame specified in \code{x} representing
#'                        the nested grouping structure for computing cluster-robust
#'                        standard errors. Note that specifying a cluster variables
#'                        does not have any effect on the information criteria,
#'                        but on the Vuong-Lo-Mendell-Rubin likelihood ratio test
#'                        of model fit.
#' @param folder          a character vector with six character strings for specifying
#'                        the names of the six folder representing different
#'                        variance-covariance structures for conducting LCA with
#'                        continuous indicator variables. There is only one folder
#'                        for LCA with all other variable types which is called
#'                        \code{"LCA_1-x_Classes"} with \code{x} being the maximum
#'                        number of classes specified in the argument \code{classes}.
#' @param file            a character string naming the Mplus data file with or
#'                        without the file extension '.dat', e.g., \code{"Data_LCA.dat"}
#'                        (default) or \code{"Data_LCA"}.
#' @param write           a character string or character vector indicating whether
#'                        to create the six folders specified in the argument
#'                        \code{folder} (\code{"folder"}), to write the matrix or
#'                        data frame specified in \code{x} into a Mplus data file
#'                        (\code{"data"}), and write the Mplus input files into
#'                        the six folders specified in the argument \code{folder}
#'                        (\code{"input"}). By default, the function creates the
#'                        folders, writes the Mplus data file, and writes the Mplus
#'                        input files into the folders.
#' @param useobservations a character string indicating the conditional statement
#'                        to select observations.
#' @param missing         a numeric value or character string representing missing
#'                        values (\code{NA}) in the Mplus data set. This values
#'                        or character string will be specified in the Mplus input
#'                        file as \code{MISSING IS ALL(missing)}. By default,
#'                        \code{-99} is used to represent missing values.
#' @param classes         an integer value specifying the maximum number of classes
#'                        for the latent class analysis. By default, LCA with
#'                        a maximum of 6 classes is specified (i.e., \emph{k} = 1
#'                        to \emph{k} = 6).
#' @param estimator       a character string for specifying the \code{ESTIMATOR}
#'                        option in Mplus. By default, the estimator \code{"MLR"}
#'                        is used.
#' @param starts          a vector with two integer values for specifying the
#'                        \code{STARTS} option in Mplus. The first number represents
#'                        the number of random sets of starting values to generate
#'                        in the initial stage and the second number represents the
#'                        optimizations to use in the final stage. By default, 500
#'                        random sets of starting values are generated and 100
#'                        optimizations are carried out in the final stage.
#' @param stiterations    an integer value specifying the \code{STITERATIONS} option
#'                        in Mplus. The numeric value represents the maximum number
#'                        of iterations allowed in the initial stage. By default,
#'                        50 iterations are requested.
#' @param lrtbootstrap    an integer value for specifying the \code{LRTBOOTSTRAP}
#'                        option in Mplus when requesting a parametric bootstrapped
#'                        likelihood ratio test (i.e., \code{output = "TECH14"}).
#'                        The value represents the number of bootstrap draws to
#'                        be used in estimating the \emph{p}-value of the parametric
#'                        bootstrapped likelihood ratio test. By default, 1000
#'                        bootstrap draws are requested.
#' @param lrtstarts       a vector with four integer values for specifying the
#'                        \code{LRTSTARTS} option in Mplus when requesting a
#'                        parametric bootstrapped likelihood ratio test (i.e.,
#'                        \code{output = "TECH14"}). The values specify the number
#'                        of starting values to use in the initial stage and the
#'                        number of optimizations to use in the final stage for
#'                        the \code{k - 1} and \code{k} classes model when the
#'                        data generated by bootstrap draws are analyzed. By default,
#'                        0 random sets of starting values in the initial stage
#'                        and 0 optimizations in the final stage are used for the
#'                        \code{k - 1} classes model and 100 random sets of starting
#'                        values in the initial stage and 50 optimizations in the
#'                        final stage are used for the \code{k} class model.
#' @param processors      an integer value for specifying the \code{PROCESSORS}
#'                        option in Mplus. The value specifies the number of
#'                        processors and threads to be used for parallel computing
#'                        to increase computational speed. By default, 8 processors
#'                        and threads are used for parallel computing.
#' @param output          a character string or character vector specifying the
#'                        \code{TECH} options in the \code{OUTPUT} section in Mplus,
#'                        i.e., \code{SVALUES} to request input statements that
#'                        contain parameter estimates from the analysis, \code{CINTERVAL}
#'                        to request confidence intervals, \code{TECH7} to request
#'                        sample statistics for each class using raw data weighted
#'                        by the estimated posterior probabilities for each class,
#'                        \code{TECH8} to request the optimization history in
#'                        estimating the model, \code{TECH11} to request the
#'                        Lo-Mendell-Rubin likelihood ratio test of model fit,
#'                        and \code{TECH14} to request a parametric bootstrapped
#'                        likelihood ratio test. By default, \code{SVALUES} and
#'                        \code{TECH11} are requested. Note that \code{TECH11}
#'                        is only available for the \code{MLR} estimator.
#' @param replace.inp     logical: if \code{TRUE}, all existing input files in the
#'                        folder specified in the argument \code{folder} are replaced.
#' @param run.mplus       logical: if \code{TRUE}, all models in the folders specified
#'                        in the argument \code{folder} are estimated by using the
#'                        \code{run.mplus} function in the R package \code{misty}.
#' @param Mplus           a character string for specifying the name or path of
#'                        the Mplus executable to be used for running models. This
#'                        covers situations where Mplus is not in the system's path,
#'                        or where one wants to test different versions of the Mplus
#'                        program. Note that there is no need to specify this argument
#'                        for most users since it has intelligent defaults.
#' @param replace.out     a character string for specifying three settings, i.e.,
#'                        \code{"always"} to run all models regardless of whether
#'                        an output file for the model exists, \code{"never"} (default)
#'                        to not run any model that has an existing output file,
#'                        and \code{"modifiedDate"} to only runs a model if the
#'                        modified date for the input file is more recent than
#'                        the output file modified date.
#' @param check           logical: if \code{TRUE}, argument specification is checked.
#'
#' @details
#' Latent class analysis (LCA) is a model-based clustering and classification
#' method used to identify qualitatively different classes of observations which
#' are unknown and must be inferred from the data. LCA can accommodate continuous,
#' count, binary, ordered categorical, and unordered categorical indicators. LCA
#' with continuous indicator variables are also known as latent profile analysis
#' (LPA). In LPA, the within-profile variance-covariance structures represent
#' different assumptions regarding the variance and covariance of the indicator
#' variables both within and between latent profiles. As the best within-profile
#' variance-covariance structure is not known a priori, all of the different
#' structures must be investigated to identify the best model (Masyn, 2013). This
#' function specifies six different variance-covariance structures labeled A to F
#' (see Table 1 in Patterer et al, 2023):
#' \describe{
#' \item{\strong{Model A}}{The within-profile variance is constrained to be
#' profile-invariant and covariances are constrained to be 0 in all profiles
#' (i.e., equal variances across profiles and no covariances among indicator
#' variables). This is the default setting in Mplus.}
#' \item{\strong{Model B}}{The within-profile variance is profile-varying and
#' covariances are constrained to be 0 in all profiles (i.e., unequal variances
#' across profiles and no covariances among indicator variables).}
#' \item{\strong{Model C}}{The within-profile variance is constrained to be
#' profile-invariant and covariances are constrained to be equal in all profiles
#' (i.e., equal variances and covariances across profiles).}
#' \item{\strong{Model D}}{The within-profile variance is constrained to be
#' profile-invariant and covariances are profile-varying (i.e., equal variances
#' across profiles and unequal covariances across profiles).}
#' \item{\strong{Model E}}{The within-profile variances are profile-varying and
#' covariances are constrained to be equal in all profiles (i.e., unequal
#' variances across profiles and equal covariances across profiles).}
#' \item{\strong{Model F}}{The within-class variance and covariances are both
#' profile-varying (i.e., unequal variances and covariances across profiles).}
#' }
#'
#' @author
#' Takuya Yanagida \email{takuya.yanagida@@univie.ac.at}
#'
#' @seealso
#' \code{\link{result.lca}}, \code{\link{run.mplus}}, \code{\link{read.mplus}},
#' \code{\link{write.mplus}}
#'
#' @references
#' Masyn, K. E. (2013). Latent class analysis and finite mixture modeling. In T. D.
#' Little (Ed.), \emph{The Oxford handbook of quantitative methods: Statistical analysis}
#' (pp. 551–611). Oxford University Press.
#'
#' Muthen, L. K., & Muthen, B. O. (1998-2017). \emph{Mplus User's Guide} (8th ed.).
#' Muthen & Muthen.
#'
#' Patterer, A. S., Yanagida, T., Kühnel, J., & Korunka, C. (2023). Daily receiving
#' and providing of social support at work: Identifying support exchange patterns
#' in hierarchical data. \emph{Journal of Work and Organizational Psychology, 32}(4),
#' 489-505. https://doi.org/10.1080/1359432X.2023.2177537
#'
#' @return
#' Returns an object of class \code{misty.object}, which is a list with following
#' entries:
#'
#' \item{\code{call}}{function call}
#' \item{\code{type}}{type of analysis}
#' \item{\code{x}}{matrix or data frame specified in the argument x}
#' \item{\code{args}}{specification of function arguments}
#' \item{\code{result}}{list with six entries for each of the variance-covariance
#'                      structures and Mplus inputs based on different number
#'                      of profiles in case of continuous indicators or list of
#'                      Mplus inputs based on different number of classes in case
#'                      of count, ordered or unordered categorical indicators.}
#'
#' @export
#'
#' @examples
#' \dontrun{
#' # Load data set "HolzingerSwineford1939" in the lavaan package
#' data("HolzingerSwineford1939", package = "lavaan")
#'
#' #--------------------------------------------------------
#' # LCA with k = 1 to k = 8 profiles, continuous indicators
#' # Input statements that contain parameter estimates
#' # Vuong-Lo-Mendell-Rubin LRT and bootstrapped LRT
#' mplus.lca(HolzingerSwineford1939, ind = c("x1", "x2", "x3", "x4"),
#'           classes = 8, output = c("SVALUES", "TECH11", "TECH14"))
#'
#' #--------------------------------------------------------
#' # LCA with k = 1 to k = 6 profiles, ordered categorical indicators
#' # Select observations with ageyr <= 13
#' # Estimate all models in Mplus
#' mplus.lca(round(HolzingerSwineford1939[, -5]), ind = c("x1", "x2", "x3", "x4"),
#'           type = "categorical", useobservations = "ageyr <= 13",
#'           run.mplus = TRUE)
#' }
mplus.lca <- function(x, ind = NULL,
                      type = c("continuous", "count", "categorical", "nominal"),
                      cluster = NULL,
                      folder = c("A_Invariant-Theta_Diagonal-Sigma",
                                 "B_Varying-Theta_Diagonal-Sigma",
                                 "C_Invariant-Theta_Invariant-Unrestrictred-Sigma",
                                 "D_Invariant-Theta_Varying-Unrestricted-Sigma",
                                 "E_Varying-Theta_Invariant-Unrestricted-Sigma",
                                 "F_Varying-Theta_Varying-Unrestricted-Sigma"),
                      file = "Data_LCA.dat", write = c("all", "folder", "data", "input"),
                      useobservations = NULL, missing = -99, classes = 6, estimator = "MLR",
                      starts = c(100, 50), stiterations = 10, lrtbootstrap = 1000,
                      lrtstarts = c(0, 0, 100, 50), processors = 8,
                      output = c("all", "SVALUES", "CINTERVAL", "TECH7", "TECH8", "TECH11", "TECH14"),
                      replace.inp = FALSE, run.mplus = FALSE, Mplus = "Mplus",
                      replace.out = c("always", "never", "modifiedDate"), check = TRUE) {

  #_____________________________________________________________________________
  #
  # Initial Check --------------------------------------------------------------

  # Check if input 'x' is missing
  if (isTRUE(missing(x))) { stop("Input for the argument 'x' is missing.", call. = FALSE) }

  # Check if input 'x' is NULL
  if (isTRUE(is.null(x))) { stop("Input specified for the argument 'x' is NULL.", call. = FALSE) }

  #_____________________________________________________________________________
  #
  # Input Check ----------------------------------------------------------------

  # Check input 'check'
  if (isTRUE(!is.logical(check))) { stop("Please specify TRUE or FALSE for the argument 'check'.", call. = FALSE) }

  if (isTRUE(check)) {

    # Check variable names in 'x'
    if (isTRUE(any(nchar(colnames(x)) > 8L))) { stop(paste0("Variables names in the matrix or data frame specified in 'x' have more than 8 characters: ", paste0(colnames(x)[which(nchar(colnames(x)) > 8L)], collapse = ", ")), call. = FALSE) }

    # Check 'ind' in 'x'
    if (isTRUE(any(!ind %in% colnames(x)))) { stop(paste0("Variables specified in 'ind' were not all found in the matrix or data frame specified in 'x': ", paste0(ind[which(!ind %in% colnames(x))], collapse = ", ")), call. = FALSE) }

    # Check 'type'
    if (isTRUE(!all(type %in% c("continuous", "count", "categorical", "nominal")))) { stop("Character string in the argument 'type' does not match with \"continuous\", \"count\", \"categorical\", or \"nominal\".", call. = FALSE) }

    # Check 'cluster' in 'x'
    if (isTRUE(!cluster %in% colnames(x))) { stop("Cluster variable specified in 'cluster' was not found in the matrix or data frame specified in 'x'.", call. = FALSE) }

    # Check 'folder'
    if (isTRUE(length(folder) != 6L || !is.character(folder))) { stop("Please specify a character vector with six entries for the argument 'folder'.", call. = FALSE) }

    # Check 'file'
    if (isTRUE(length(file) != 1L || !is.character(file))) { stop("Please specify a character string for the argument 'file'.", call. = FALSE) }

    # Check 'write'
    if (isTRUE(!all(write %in% c("all", "folder", "data", "input")))) { stop("Character string in the argument 'write' does not match with \"folder\", \"data\", or \"input\".", call. = FALSE) }

    # Check 'missing'
    if (isTRUE(length(missing) != 1L)) { stop("Please specify a numeric value or character string for the argument 'missing'.", call. = FALSE) }

    # Check 'classes'
    if (isTRUE(length(classes) != 1L || classes %% 1L != 0L)) { stop("Please specify a numeric value for the argument 'classes'.", call. = FALSE) }

    # Check 'starts'
    if (isTRUE(length(starts) != 2L) || any(starts %% 1L != 0L)) { stop("Please specify a vector with two integer values for the argument 'starts'.", call. = FALSE) }

    # Check 'starts'
    if (isTRUE(starts[2L] > starts[1L])) { stop("The second value must be less than or equal the first value in the argument 'starts'.", call. = FALSE) }

    # Check 'stiterations'
    if (isTRUE(length(stiterations) != 1L || stiterations %% 1L != 0L)) { stop("Please specify an integer value for the argument 'stiterations'.", call. = FALSE) }

    # Check 'lrtbootstrap'
    if (isTRUE(length(lrtbootstrap) != 1L || lrtbootstrap %% 1L != 0L)) { stop("Please specify an integer value for the argument 'lrtbootstrap'.", call. = FALSE) }

    # Check 'lrtstarts'
    if (isTRUE(length(lrtstarts) != 4L || any(lrtstarts %% 1L != 0L))) { stop("Please specify a vector with four integer values for the argument 'lrtstarts'.", call. = FALSE) }

    # Check 'lrtstarts'
    if (isTRUE(lrtstarts[2L] > lrtstarts[1L])) { stop("The second value must be less than or equal the first value in the argument 'lrtstarts'.", call. = FALSE) }

    # Check 'lrtstarts'
    if (isTRUE(lrtstarts[4L] > lrtstarts[3L])) { stop("The fourth value must be less than or equal the third value in the argument 'lrtstarts'.", call. = FALSE) }

    # Check 'processors'
    if (isTRUE(length(processors) != 1L || processors %% 1L != 0L)) { stop("Please specify an integer value for the argument 'processors'.", call. = FALSE) }

    ## Check input 'print' ##
    if (isTRUE(!all(output %in% c("all", "SVALUES", "CINTERVAL", "TECH7", "TECH8", "TECH11", "TECH14")))) { stop("Character string in the argument 'output' does not match with \"SVALUES\", \"CINTERVAL\", \"TECH7\", \"TECH8\", \"TECH11\", or \"TECH14\".", call. = FALSE) }

    ## Check input 'replace.inp' ##
    if (isTRUE(!is.logical(replace.inp))) { stop("Please specify TRUE or FALSE for the argument 'replace.inp '.", call. = FALSE) }

    ## Check input 'run.mplus' ##
    if (isTRUE(!is.logical(run.mplus))) { stop("Please specify TRUE or FALSE for the argument 'run.mplus '.", call. = FALSE) }

    ## Check input 'replace.out' ##
    if (isTRUE(!all(replace.out %in% c("always", "never", "modifiedDate")))) { stop("Character string in the argument 'replace.out ' does not match with \"always\", \"never\",  or \"modifiedDate\".", call. = FALSE) }

    ## Check input 'check' ##
    if (isTRUE(!is.logical(check))) { stop("Please specify TRUE or FALSE for the argument 'check'.", call. = FALSE) }

  }

  #_____________________________________________________________________________
  #
  # Data and Arguments ---------------------------------------------------------

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ## Type ####

  if (isTRUE(all(c("continuous", "count", "categorical", "nominal") %in% type))) {

    type <- "continuous"

  } else {

    if (isTRUE(length(type) != 1L)) { stop("Please specify a character string for the argument 'type'", call. = FALSE) }

  }

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ## Folder ####

  if (isTRUE(type != "continuous")) { folder <- paste0("LCA_1-", classes, "_Classes") }

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ## Write ####

  if (isTRUE(all(c("all", "folder", "data", "input") %in% write))) { write <- c("folder", "data", "input") }

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ## Output ####

  if (isTRUE(all(c("all", "SVALUES", "CINTERVAL", "TECH7", "TECH8", "TECH11", "TECH14") %in% output))) { output <- c("SVALUES", "TECH11") }

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ## replaceOutfile ####

  if (isTRUE(all(c("always", "never", "modifiedDate") %in% replace.out))) {

    replace.out <- "never"

  } else {

    if (isTRUE(length(replace.out) != 1L)) { stop("Please specify a character string for the argument 'replace.out'", call. = FALSE) }

  }

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ## Variabla Names ####

  # Split variables names in chucks of 8
  var.x <- split(colnames(x), ceiling(seq_along(colnames(x)) / 8L))

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ## Indicator Names ####

  # Number of characters
  ind.nchar <- nchar(paste(ind, collapse = " "))

  if (ind.nchar <= 70L) { ind.x <- list(ind)} else { ind.x <- split(ind, ceiling(seq_along(ind) / 7L)) }

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ## Indicator Covariances ####

  # Up to 8 indicator variables
  if (isTRUE(ind.nchar <= 70L)) {

    ind.cov <- paste0("            ", paste0(c(ind, "WITH"), collapse = " "), "\n",
                      "            ", paste0(ind, collapse = " "), ";")

  # More than 8 indicator variables
  } else {

    ind.cov <- paste0(paste0("            ", apply(combn(ind, m = 2L), 2L, paste0, collapse = " WITH "), collapse = ";\n"), ";")

  }

  #_____________________________________________________________________________
  #
  # Main Function --------------------------------------------------------------

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ## Write Data ####

  if (isTRUE("data" %in% write)) { write.table(x, file = file, quote = FALSE, na = as.character(missing), row.names = FALSE, col.names = FALSE) }

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ## Data, Variable, Analysis, and Output ####

  # Data, Variable, and Analysis
  mod.dva <- paste0("DATA:       FILE IS ../",  file, ";\n\n",
                    "VARIABLE:   NAMES ARE\n",
                    "            ",   paste0(unlist(lapply(var.x, function(y) paste0(y, collapse = " "))), collapse = "\n            "), ";\n\n",
                    "            USEVARIABLES ARE\n",
                    "            ",   paste0(unlist(lapply(ind.x, function(y) paste0(y, collapse = " "))), collapse = "\n            "), ";\n\n",
                    if (isTRUE(type != "continuous")) { paste0("            ", toupper(type), " ARE\n",
                                                               "            ", paste0(unlist(lapply(ind.x, function(y) paste0(y, collapse = " "))), collapse = "\n            "), ";\n\n") },
                    if (isTRUE(!is.null(useobservations))) { paste0("            USEOBSERVATIONS ARE ", useobservations, ";\n\n") },
                    "            MISSING IS ALL(", missing, ");\n\n",
                    if (isTRUE(!is.null(cluster))) { paste0("            CLUSTER IS ", cluster, ";\n\n") },
                    "            CLASSES ARE c(_classes_);\n\n",
                    if (isTRUE(!is.null(cluster))) { "ANALYSIS:   TYPE IS MIXTURE COMPLEX;\n" } else { "ANALYSIS:   TYPE IS MIXTURE;\n" },
                    "            ESTIMATOR IS ", estimator, ";\n",
                    "            STARTS ARE ", paste0(starts, collapse = " "), ";\n",
                    "            STITERATIONS ARE ", stiterations, ";\n",
                    if (isTRUE("TECH14" %in% output)) { paste0("            LRTBOOTSTRAP IS ", lrtbootstrap, ";\n",
                                                               "            LRTSTARTS ARE ", paste0(lrtstarts, collapse = " "), ";\n") },
                    "            PROCESSORS ARE ", processors, ";\n\n")

  # Output
  mod.out <- paste0("OUTPUT:     ", paste0(output, collapse = " "), ";")

  # Output for k = 1 profile
  mod.out.1C <-  paste0(misty::chr.trim(strsplit(misty::chr.gsub(c("TECH11", "TECH14"), c("", ""), mod.out), ";")), ";")

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ## Continuous Indicators ####

  if (isTRUE(type == "continuous")) {

    #...................
    ### Create Folder ####

    if (isTRUE("folder" %in% write)) { suppressWarnings(invisible(lapply(folder, dir.create))) }

    #...................
    ### Model A ####

    # Paste syntax
    mod.A <- list()
    for (i in seq_len(classes)) {

      mod.A[[i]] <- paste0(# Title
                           "TITLE:      Latent Profile Analysis (LPA)\n",
                           "            A: Profile-Invariant Theta, Diagonal-Sigma\n\n",
                           # Data, Variable, and Analysis
                           sub("_classes_", i, mod.dva),
                           # Output
                           if (isTRUE(i != 1L)) { mod.out } else { mod.out.1C })

    }

    #...................
    ### Model B ####

    mod.B <- list()
    for (i in seq_len(classes)) {

      # Model specifcation
      model <- paste0("            %c#_classes_%\n",
                      "            ", paste0(unlist(lapply(ind.x, function(y) paste0(y, collapse = " "))), collapse = "\n            "), ";\n\n")

      # Paste syntax
      mod.B[[i]] <- paste0(# Title
                           "TITLE:      Latent Profile Analysis (LPA)\n",
                           "            B: Profile-Varying Theta, Diagonal-Sigma\n\n",
                           # Data, Variable, and Analysis
                           sub("_classes_", i, mod.dva),
                           # Model
                           "MODEL:            \n",
                           paste0(sapply(seq_len(i), function(y) sub("_classes_", y, model)), collapse = ""),
                           # Output
                           if (isTRUE(i != 1L)) { mod.out } else { mod.out.1C })

    }

    #...................
    ### Model C ####

    mod.C <- list()
    for (i in seq_len(classes)) {

      # Paste syntax
      mod.C[[i]] <- paste0(# Title
                           "TITLE:      Latent Profile Analysis (LPA)\n",
                           "            C: Profile-Invariant Theta, Profile-Invariant Unrestricted Sigma\n\n",
                           # Data, Variable, and Analysis
                           sub("_classes_", i, mod.dva),
                           # Model
                           "MODEL:            \n",
                           "            %OVERALL%\n",
                           ind.cov, "\n\n",
                           # Output
                           if (isTRUE(i != 1L)) { mod.out } else { mod.out.1C })

    }

    #...................
    ### Model D ####

    mod.D <- list()
    for (i in seq_len(classes)) {

      # Model specifcation
      model <- paste0("            %c#_classes_%\n", ind.cov, "\n\n")

      # Paste syntax
      mod.D[[i]] <- paste0(# Title
                           "TITLE:      Latent Profile Analysis (LPA)\n",
                           "            D: Profile-Invariant Theta, Profile-Varying Unrestricted Sigma\n\n",
                           # Data, Variable, and Analysis
                           sub("_classes_", i, mod.dva),
                           # Model
                           "MODEL:            \n",
                           "            %OVERALL%\n",
                           ind.cov, "\n\n",
                           paste0(sapply(seq_len(i), function(y) sub("_classes_", y, model)), collapse = ""),
                           # Output
                           if (isTRUE(i != 1L)) { mod.out } else { mod.out.1C })

    }

    #...................
    ### Model E ####

    mod.E <- list()
    for (i in seq_len(classes)) {

      # Model specifcation
      model <- paste0("            %c#_classes_%\n",
                      "            ", paste0(unlist(lapply(ind.x, function(y) paste0(y, collapse = " "))), collapse = "\n            "), ";\n\n")

      # Paste syntax
      mod.E[[i]] <- paste0(# Title
                           "TITLE:      Latent Profile Analysis (LPA)\n",
                           "            E: Profile-Varying Theta, Profile-Invariant Unrestricted Sigma\n\n",
                           # Data, Variable, and Analysis
                           sub("_classes_", i, mod.dva),
                           # Model
                           "MODEL:            \n",
                           "            %OVERALL%\n",
                           ind.cov, "\n\n",
                           paste0(sapply(seq_len(i), function(y) sub("_classes_", y, model)), collapse = ""),
                           # Output
                           if (isTRUE(i != 1L)) { mod.out } else { mod.out.1C })

    }

    #...................
    ### Model F ####

    mod.F <- list()
    for (i in seq_len(classes)) {

      # Model specifcation
      model <- paste0("            %c#_classes_%\n",
                      "            ", paste0(unlist(lapply(ind.x, function(y) paste0(y, collapse = " "))), collapse = "\n            "), ";\n\n",
                      ind.cov, "\n\n")

      # Paste syntax
      mod.F[[i]] <- paste0(# Title
                           "TITLE:      Latent Profile Analysis (LPA)\n",
                           "            F: Profile-Varying Theta, Profile-Varying Unrestricted Sigma\n\n",
                           # Data, Variable, and Analysis
                           sub("_classes_", i, mod.dva),
                           # Model
                           "MODEL:            \n",
                           "            %OVERALL%\n",
                           ind.cov, "\n\n",
                           paste0(sapply(seq_len(i), function(y) sub("_classes_", y, model)), collapse = ""),
                           # Output
                           if (isTRUE(i != 1L)) { mod.out } else { mod.out.1C })

    }

    #...................
    ### Result List ####

    mod <- list(mod.A, mod.B, mod.C, mod.D, mod.E, mod.F)

    #...................
    ### write Mplus syntax ####

    if (isTRUE("input" %in% write)) {

      #### Model A
      suppressWarnings(invisible(sapply(seq_len(classes), function(y) {

        # Replace existing input files
        if (isTRUE(replace.inp)) {

          writeLines(mod.A[[y]], paste0(folder[1L], "/A_LPA-", y, ".inp"))

        # Do not replace existing input files
        } else {

          if (isTRUE(!paste0("A_LPA-", y, ".inp") %in% list.files(folder[1L]))) {

            writeLines(mod.A[[y]], paste0(folder[1L], "/A_LPA-", y, ".inp"))

          }

        }

      })))

      #### Model B
      suppressWarnings(invisible(sapply(seq_len(classes), function(y) {

        # Replace existing input files
        if (isTRUE(replace.inp)) {

          writeLines(mod.B[[y]], paste0(folder[2L], "/B_LPA-", y, ".inp"))

        # Do not replace existing input files
        } else {

          if (isTRUE(!paste0("B_LPA-", y, ".inp") %in% list.files(folder[2L]))) {

            writeLines(mod.B[[y]], paste0(folder[2L], "/B_LPA-", y, ".inp"))

          }

        }

      })))

      #### Model C
      suppressWarnings(invisible(sapply(seq_len(classes), function(y) {

        # Replace existing input files
        if (isTRUE(replace.inp)) {

          writeLines(mod.C[[y]], paste0(folder[3L], "/C_LPA-", y, ".inp"))

        # Do not replace existing input files
        } else {

          if (isTRUE(!paste0("C_LPA-", y, ".inp") %in% list.files(folder[3L]))) {

            writeLines(mod.C[[y]], paste0(folder[3L], "/C_LPA-", y, ".inp"))

          }

        }

      })))

      #### Model D
      suppressWarnings(invisible(sapply(seq_len(classes), function(y) {

        # Replace existing input files
        if (isTRUE(replace.inp)) {

          writeLines(mod.D[[y]], paste0(folder[4L], "/D_LPA-", y, ".inp"))

        # Do not replace existing input files
        } else {

          if (isTRUE(!paste0("D_LPA-", y, ".inp") %in% list.files(folder[4L]))) {

            writeLines(mod.D[[y]], paste0(folder[4L], "/D_LPA-", y, ".inp"))

          }

        }

      })))

      #### Model E
      suppressWarnings(invisible(sapply(seq_len(classes), function(y) {

        # Replace existing input files
        if (isTRUE(replace.inp)) {

          writeLines(mod.E[[y]], paste0(folder[5L], "/E_LPA-", y, ".inp"))

        # Do not replace existing input files
        } else {

          if (isTRUE(!paste0("E_LPA-", y, ".inp") %in% list.files(folder[5L]))) {

            writeLines(mod.E[[y]], paste0(folder[5L], "/E_LPA-", y, ".inp"))

          }

        }

      })))

      #### Model F
      suppressWarnings(invisible(sapply(seq_len(classes), function(y) {

        # Replace existing input files
        if (isTRUE(replace.inp)) {

          writeLines(mod.F[[y]], paste0(folder[6L], "/F_LPA-", y, ".inp"))

        # Do not replace existing input files
        } else {

          if (isTRUE(!paste0("F_LPA-", y, ".inp") %in% list.files(folder[6L]))) {

            writeLines(mod.F[[y]], paste0(folder[6L], "/F_LPA-", y, ".inp"))

          }

        }

      })))

    }

    #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    ## Run Mplus ####

    if (isTRUE(run.mplus)) { sapply(folder, function(y) misty::run.mplus(target = file.path(getwd(), y), recursive = FALSE, Mplus = Mplus, replaceOutfile = replace.out)) }

  #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ## Count, Categorical, and Nominal Indicators ####

  } else {

    #...................
    ### Create Folder ####

    if (isTRUE("folder" %in% write)) { suppressWarnings(invisible(dir.create(paste0("LCA_1-", classes, "_Classes")))) }

    #...................
    ### LCA Models ####

    # Paste syntax
    mod <- list()
    for (i in seq_len(classes)) {

      mod[[i]] <- paste0(# Title
                         "TITLE:      Latent Class Analysis (LCA)\n\n",
                         # Data, Variable, and Analysis
                         sub("_classes_", i, mod.dva),
                         # Output
                         if (isTRUE(i != 1L)) { mod.out } else { mod.out.1C })

    }

    #...................
    ### write Mplus syntax ####

    if (isTRUE("input" %in% write)) {

      suppressWarnings(invisible(sapply(seq_len(classes), function(y) writeLines(mod[[y]], paste0("LCA_1-", classes, "_Classes/", "LCA-", y, ".inp")))))

    }

    #~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    ## Run Mplus ####

    if (isTRUE(run.mplus)) { misty::run.mplus(target = file.path(getwd(), paste0("LCA_1-", classes, "_Classes")), recursive = FALSE, Mplus = Mplus, replaceOutfile = replace.out) }

  }

  #_____________________________________________________________________________
  #
  # Return object --------------------------------------------------------------

  object <- list(call = match.call(),
                 type = "mplus.lca",
                 x = x,
                 args = list(ind = ind, type = type, cluster = cluster, folder = folder,
                             file = file, write = write, useobservations = useobservations,
                             missing = missing, classes = classes, estimator = estimator,
                             starts = starts, stiterations = stiterations, lrtbootstra = lrtbootstrap,
                             lrtstarts = lrtstarts, processors = processors, output = output,
                             replace.inp = replace.inp, run.mplus = run.mplus, Mplus = Mplus,
                             replace.out = replace.out, check = check),
                 result = mod)

  class(object) <- "misty.object"

  return(invisible(object))

}