相关疑难解决方法(0)

我有一个带有分类变量的数据框,其中包含可变长度的字符串列表(这很重要,因为否则此问题将与此或此重复),例如:

df <- data.frame(x = 1:5)
df$y <- list("A", c("A", "B"), "C", c("B", "D", "C"), "E")
df

  x       y
1 1       A
2 2    A, B
3 3       C
4 4 B, D, C
5 5       E

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并且所需的形式是在任何地方看到的每个唯一字符串的虚拟变量df$y,即:

data.frame(x = 1:5, A = c(1,1,0,0,0), B = c(0,1,0,1,0), C = c(0,0,1,1,0), D = c(0,0,0,1,0), E = c(0,0,0,0,1))

  x A B C D E
1 1 1 0 0 0 0
2 2 1 …

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什么是一种有效的方法(欢迎包括非基础包的任何解决方案)将虚拟变量折叠回一个因子.

   race.White race.Hispanic race.Black race.Asian
1           1             0          0          0
2           0             0          0          1
3           1             0          0          0
4           0             0          1          0
5           0             0          0          1
6           0             1          0          0
7           1             0          0          0
8           1             0          0          0
9           1             0          0          0
10          0             0          1          0

期望的输出:

       race
1     White
2     Asian
3     White
4     Black
5     Asian
6  Hispanic
7     White
8     White
9     White
10    Black

数据:

dat <- …

假设我有一个看起来像这样的数据框：

df1=structure(list(Name = structure(1:6, .Label = c("N1", "N2", "N3", 
                                                    "N4", "N5", "N6", "N7"), class = "factor"), sector = structure(c(4L, 
                                                                                                                     4L, 4L, 3L, 3L, 2L), .Label = c("other stuff", "Private for-profit, 4-year or above", 
                                                                                                                                                     "Private not-for-profit, 4-year or above", "Public, 4-year or above"
                                                                                                                     ), class = "factor"), flagship = c(1, 0, 0, 0, 0, 0)), .Names = c("Name", 
                                                                                                                                                                                       "sector", "flagship"), row.names = c(NA, 6L), class = "data.frame")

我想创建一个新的因子变量“ Sector”。我可以用很多行代码来做很长的路，但是我敢肯定有一种更有效的方法。

现在这就是我正在做的：

df1$PublicFlag=0
df1$PublicFlag[df1$sector=="Public, 4-year or above" & df1$flagship==1]=1
df1$Public=0
df1$Public[df1$sector=="Public, 4-year or …