Small helper function. Checks if all expected columns are in the data frame and if not, adds a column with all missing variables in the data. Thus, the columns will be made explicitly missing in the data frame.
Value
A data frame with at least all the columns named in columns.
The added columns will be of class character.
Examples
add_missing_columns(head(iris), c("important_column1", "important_column2"))
#> Sepal.Length Sepal.Width Petal.Length Petal.Width Species important_column1
#> 1 5.1 3.5 1.4 0.2 setosa <NA>
#> 2 4.9 3.0 1.4 0.2 setosa <NA>
#> 3 4.7 3.2 1.3 0.2 setosa <NA>
#> 4 4.6 3.1 1.5 0.2 setosa <NA>
#> 5 5.0 3.6 1.4 0.2 setosa <NA>
#> 6 5.4 3.9 1.7 0.4 setosa <NA>
#> important_column2
#> 1 <NA>
#> 2 <NA>
#> 3 <NA>
#> 4 <NA>
#> 5 <NA>
#> 6 <NA>