ji.ds.is.null: tests whether an object is NULL
In datashield/ji.dev.cl: ji.dev.cl

Description Usage Arguments Value Author(s) Examples

this function is similar to R function is.null

1	ji.ds.is.null(datasources = NULL, xvect = NULL)

`datasources`	a list of opal object(s) obtained after login in to opal servers; these objects hold also the data assign to R, as `dataframe`, from opal datasources.
`xvect`	a vector to be tested

a logic value (TRUE if xvect is null and FALSE otherwise)

Gaye, A. (amadou.gaye

{

# load that contains the login details
data(logindata)

# login
opals <- datashield.login(logins=logindata,assign=TRUE)

# Example 1: Test whether LAB_TSC variable is NULL
ji.ds.is.null(datasources=opals, xvect=quote(D$LAB_TSC))

}