Julia 1.0 Programming Cookbook

How to do it...

In this recipe, we present two approaches to calculating the final grade:

1. In the first approach, we start by defining a function that is used to calculate the grade:

julia> function get_grade(final, midterm, takehome)           (ismissing(final) || final < 50) && return "fail"           if final < 75 && coalesce(midterm, 0) < 50 && coalesce(takehome, 0) < 50               "fail"           else               "pass"           end       endget_grade (generic function with 1 method)

2. Then, we can define a new column in our data frame:

julia> df.grade = get_grade.(df.Final, df.Midterm, df.TakeHome);

3. Another approach is to use the eachrow iterator, which returns data frame-like objects along with the map function and the do block, like this:

julia> df.grade2 = map(eachrow(df)) do r coalesce(r.Final, ...