我希望通过对第二个变量进行分组来计算唯一值的数量,然后将计数添加到现有data.frame作为新列.例如,如果现有数据框如下所示:
color type
1 black chair
2 black chair
3 black sofa
4 green sofa
5 green sofa
6 red sofa
7 red plate
8 blue sofa
9 blue plate
10 blue chair
我想为每个添加数据中存在color的唯一计数types:
color type unique_types
1 black chair 2
2 black chair 2
3 black sofa 2
4 green sofa 1
5 green sofa 1
6 red sofa 2
7 red plate 2
8 blue sofa 3
9 blue plate 3
10 blue chair …