bugfix to support parameter EAVtables of length 1

[RosaMGini]

in row 60 if the condition

length(unlist(EAVtables[[t]])) == 2

is replaced by

length(unlist(EAVtables[[t]])) < 3

then the function supports the case when there is only 1 parameter to be checked in the list EAVtables.

ConcePTION_CDM_EAV_tables_retrieve_column <- list()

ConcePTION_CDM_EAV_tables_retrieve_column[["SURVEY_OBSERVATIONS"]] <- list("so_source_column")

if SURVEY_OBSERVATIONS is this file

person_id,so_source_column
P00000001,A
P00000002,B

and

itemset_thisstudy[["SURVEY_OBSERVATIONS"]][[myvar]] <- list(list("B"))

then

CreateItemsetDatasets(EAVtables = ConcePTION_CDM_EAV_tables_retrieve_column,
                      study_variable_names = c("myvar"),
                      itemset = itemset_thisstudy,
                      dirinput = dirinput,
                      diroutput = diritemsets,
                      extension = c("csv"))
                      

does work. I will create an example

@DavideMessinaARS and @OlgaPaoletti