r - 合并两个表并聚合

Question

我有两个表名称和成绩，如下所示:

表:名称

Male   Female

Sam    Tina
       Anna

表:成绩

Class  Name  Grades
A      Sam   5
B      Sam   5
A      Tina  5
B      Tina  5
C      Tina  5
A      Anna  5

合并后新表应如下所示:

Class Gender Grades
A     Male   5
B     Male   5
A     Female 10
B     Female 5
C     Female 5

我尝试过groupby、merge，但它总是给我一个错误的表。 我可以使用任何函数来获取正确的表吗？谢谢!!

Answer 1

使用stack将name数据帧转换为长格式。然后照常合并，然后聚合性别和类别:

aggregate(Grades ~ Class + ind,
          merge(grades, na.omit(stack(name)), by.x = "Name", by.y = "values"), sum)
#   Class    ind Grades
# 1     A   Male      5
# 2     B   Male      5
# 3     A Female     10
# 4     B Female      5
# 5     C Female      5

#data
name <- read.table(text = "
Male Female
Sam Tina
NA Anna", header = TRUE)

grades <- read.table(text = "
Class  Name  Grades
A      Sam   5
B      Sam   5
A      Tina  5
B      Tina  5
C      Tina  5
A      Anna  5", header = TRUE)