gather exists as we want to include this extra metadata about the rows that have missing data, but I also wanted to include some extra information about the class of the data, in case we need to gather the data back into a wider, rather than long, format. Here it takes a function `visdat`, `visdat:::fingerprint`, which is currently not a particularly complex function.
Usage
gather_shadow(data)
Arguments
data
a dataframe
Value
a dataframe in long, or "molten" format, containing information about the missings