fun DataFrame.gather(key: String, value: String, columns: List<String> = this.names, convert: Boolean = false): DataFrame
Gather takes multiple columns and collapses into key-value pairs, duplicating all other columns as needed. You use gather() when you notice that you have columns that are not variables.
key - Name of the key column to create in output.
value - Name of the value column to create in output.
columns - The colums to gather. The same selectar syntax as for krangl::select is supported here
convert - If TRUE will automatically run convertType on the key column. This is useful if the
column names are actually numeric, integer, or logical.
fun DataFrame.gather(key: String, value: String, columns: ColumnSelector, convert: Boolean = false): DataFrame