R/lavaanify.grep.nonlinear.R

In TAM: Test Analysis Modules

## File Name: lavaanify.grep.nonlinear.R
## File Version: 9.07



#*** grep for nonlinear terms for factors and regressions
lavaanify.grep.nonlinear <- function( lavmodel, items ){
        lavmodel <- gsub( ";", "\n", paste(lavmodel) )
        syn <- unlist( strsplit( paste(lavmodel), split="\n") )
        syn <- gsub(" ", "", syn )
        syn <- syn[ syn !="" ]
        ind <- substring( syn, 1, 1 ) !="#"
        syn <- syn[ind]

        dfr <- data.frame("index"=seq(1,length(syn) ), "syntax"=syn )
        dfr$nonlin_loadings <- 0
        dfr$nonlin_regr <- 0
        dfr$nonlin_terms <- ""
        dfr$syntax_mod <- dfr$syntax

        #**********************************
        #**** grep for nonlinear factor loadings
        ind1 <- grep( "=~", syn  )
        ind2 <- grep("I(", syn, fixed=TRUE)
        ind <- intersect(ind1, ind2 )
        if ( length(ind) > 0 ){
            dfr$nonlin_loadings[ind] <- 1
            l1 <- unlist(lapply( strsplit( syn[ind], split="=~" ), FUN=function(hh){ hh[1] } ))
            dfr$nonlin_terms[ ind ] <- l1
                        }
        #************************************
        #***** grep for regressions on factors
        ind1 <- grep( "~", syn  )
        ind1a <- grep( "~~", syn  )
        ind1b <- grep( "=~", syn  )
        ind1 <- setdiff( ind1, c(ind1a,ind1b) )
        ind2 <- grep("I(", syn, fixed=TRUE)
        ind <- intersect(ind1, ind2 )
        if ( length(ind) > 0 ){
            dfr$nonlin_regr[ind] <- 1
            l1 <- unlist(lapply( strsplit( syn[ind], split="~" ), FUN=function(hh){ hh[2] } ))
#            l2 <- sapply( l1, FUN=function(ii){
            for (kk in seq(1,length(ind) ) ){
                    ii <- l1[kk]
                    ii <- unlist( strsplit( ii, split="+", fixed=TRUE)    )
                    ii <- grep( "I(", ii, fixed=TRUE, value=TRUE)
                    ii2 <- strsplit( ii, split="I(", fixed=TRUE )
                    ii2 <- unlist( lapply( ii2, FUN=function(hh){
                                        hh[ length(hh) ] } ) )
                    ii2 <- paste0( "I(", ii2 )
                    ii2 <- paste0( ii2, collapse=" ## " )
                    dfr$nonlin_terms[ ind[kk] ] <- ii2
                                }
                        }
        #**** collect all nonlinear terms
        nt1 <- unlist( strsplit( paste( dfr$nonlin_terms ), split=" ## " ) )
        nt1 <- unique( nt1 )
        N1 <- length(nt1)
        dfr2 <- NULL
        if ( N1 > 0 ){
            dfr2 <- data.frame( "nonlin_fac"=nt1, "nonlin_fac_rename"=paste0( "NLFAC_", 1:N1 ) )
            for ( ii in 1:N1){
               h2 <- paste(dfr$syntax_mod)
                    dfr$syntax_mod <- gsub( paste(dfr2$nonlin_fac)[ii], paste( dfr2$nonlin_fac_rename )[ii],
                                h2,  fixed=TRUE )
                            }
                dfr2$exo <- 0
                    }

        syn <- paste0( dfr$syntax_mod, collapse="\n" )
        # exogeneous nonlinear terms
        if (N1 > 0 ){
            dfr2a <- dfr2[ ! ( paste(dfr2$nonlin_fac) %in% paste( dfr$nonlin_terms)[ dfr$nonlin_loadings==1] ), ]
            if ( nrow(dfr2a) > 0 ){
                items <- c( items, paste(dfr2a$nonlin_fac_rename ) )
                dfr2$exo[ paste(dfr2$nonlin_fac_rename ) %in% paste(dfr2a$nonlin_fac_rename ) ] <- 1
                }

                    }

        if ( is.null(dfr2) ){ dfr <- NULL }
        res <- list("lavmodel"=syn, "nonlin_syntable"=dfr,
                "nonlin_factors"=dfr2, "items"=items )
        return(res)
                }