小编War*_*ang的帖子

classA = Dataset(id = ["id1", "id2", "id3", "id4", "id5"],
                        mark = [50, 69.5, 45.5, 88.0, 98.5]);

grades = Dataset(mark = [0, 49.5, 59.5, 69.5, 79.5, 89.5, 95.5],
                        grade = ["F", "P", "C", "B", "A-", "A", "A+"]);

我们可以使用 InMemorydatasets 包来进行 closejoin。

我们如何在 DataFrames 包中执行此方法。

closejoin(classA, grades, on = :mark)

closejoin(classA, grades, on = :mark, direction=:forward, border=:nearest)

以及如何在 R 中做到这一点？

ds = Dataset([[1, 1, 1, 2, 2, 2],
                        ["foo", "bar", "monty", "foo", "bar", "monty"],
                        ["a", "b", "c", "d", "e", "f"],
                        [1, 2, 3, 4, 5, 6]], [:g, :key, :foo, :bar])

在InmemoryDatasets中，transpose函数可以传递列选择器的Tuple。

transpose(groupby(ds, :g), (:foo, :bar), id = :key)

Result:

g   foo bar monty   foo_1   bar_1   monty_1
identity    identity    identity    identity    identity    identity    identity
Int64?  String? String? String? Int64?  Int64?  Int64?
1   1   a   b   c   1   2   3
2   2   d   e   f   4   5   6

问题：

我如何在 DataFrames.jl 中执行此操作？ …