internalformulaIt: Internal function to create a formula
Description
This function is not intended to be called by users.
It creates a formula style character string from its argument.
But note that it does not actually create a formula class object.
If you do not want an argument, use the empty string.
Usage
internalformulaIt(dv, iv, covariates)
Value
A character string
Arguments
dv
A character string of the dependent variable.
iv
A character string or vector of the independent variables
covariates
A character string or vector of the dependent variables