In data frames with factor variables, convert any observation with "" into
<NA>.
Arguments
- data
a data frame with factor variables.
Value
Returns the same data frame with """" replaced by <NA>
in factor variables.
Details
In a factor variable with the level """", this command will convert
this to an <NA>.
Note
When importing data from comma separated files (for example), missing
values in a categorical variable are often denoted by """. We often do not
want to treat this as a level of a factor variable in R.