r - 来自其他向量列的新列表列，带有 dplyr 和 rowwise

Question

我有下面的 tibble，我想从中创建第 4 列，它是来自 A、B 和 C 的联合向量。我知道 dplyr::unite() 可以创建一个新的字符向量，但我正在寻找创建一个带有向量的列表列。

现在 rowwise 工作，但不保留输入小标题。将 A_Vector 列保留到 C_Vector 的任何建议？

这是代码:

library(tidyverse)

My_Data <- tibble(A_Vector = rnorm(10),
                  B_Vector = rnorm(10),
                  C_Vector = rnorm(10)) %>% 
           rowwise() %>% 
           do(Port_Weights = matrix(c(.$A_Vector,.$B_Vector,.$C_Vector),3,1))

结果:

Source: local data frame [10 x 1]
Groups: <by row>

# A tibble: 10 x 1
    Port_Weights
 *        <list>
 1 <dbl [3 x 1]>
 2 <dbl [3 x 1]>
 3 <dbl [3 x 1]>
 4 <dbl [3 x 1]>
 5 <dbl [3 x 1]>
 6 <dbl [3 x 1]>
 7 <dbl [3 x 1]>
 8 <dbl [3 x 1]>
 9 <dbl [3 x 1]>
10 <dbl [3 x 1]>

这不起作用:

My_Data <- tibble(A_Vector = rnorm(10),
                  B_Vector = rnorm(10),
                  C_Vector = rnorm(10)) %>% 
  mutate(Port_Weights = rowwise() %>% do(matrix(c(.$A_Vector,.$B_Vector,.$C_Vector),3,1)))

长版本，这显然没有意义:

My_Data <- tibble(A_Vector = rnorm(10),
                  B_Vector = rnorm(10),
                  C_Vector = rnorm(10))

Data_Unite <-   My_Data %>% 
  rowwise() %>% 
  do(Port_Weights = matrix(c(.$A_Vector,.$B_Vector,.$C_Vector),3,1))

My_Data <- as.tibble(cbind(My_Data,Data_Unite))

但确实提供了追捧的结果:

# A tibble: 10 x 4
      A_Vector   B_Vector   C_Vector  Port_Weights
 *       <dbl>      <dbl>      <dbl>        <list>
 1 -1.23504457 -0.3750408 -0.4214122 <dbl [3 x 1]>
 2 -0.90678699  0.5261914  1.1191229 <dbl [3 x 1]>
 3 -0.62944085  0.5995529  0.2096462 <dbl [3 x 1]>
 4  2.06171633  1.5399094  2.2972950 <dbl [3 x 1]>
 5  0.08761555  0.1424207 -1.4758585 <dbl [3 x 1]>
 6 -1.07334432 -1.9112787  0.4820864 <dbl [3 x 1]>
 7 -0.18655423 -1.3698855  0.6672621 <dbl [3 x 1]>
 8 -0.97961789 -0.8194373 -0.4158516 <dbl [3 x 1]>
 9  0.68112936 -1.9864507  1.0193449 <dbl [3 x 1]>
10  0.61455438  0.5885380 -1.0925312 <dbl [3 x 1]>

Answer 1

数据:

library(tidyverse)

my_tibble <- tibble(A_Vector = rnorm(10),
                    B_Vector = rnorm(10),
                    C_Vector = rnorm(10))

要将列添加到数据框中，请使用 mutate而不是 do ，并使用 Map并行遍历三个向量并从每一行构造一个矩阵:

my_tibble %>% 
   mutate(Port_Weights = Map(function(...) matrix(c(...), 3, 1), A_Vector, B_Vector, C_Vector))

# A tibble: 10 x 4
#      A_Vector   B_Vector    C_Vector  Port_Weights
#         <dbl>      <dbl>       <dbl>        <list>
# 1  0.62674726 -0.5432169 -1.66763618 <dbl [3 x 1]>
# 2 -0.47346722 -0.4436020 -1.04892634 <dbl [3 x 1]>
# 3  0.19059238 -1.6733052  2.79275828 <dbl [3 x 1]>
# 4 -0.23501873 -1.1664704 -0.19324676 <dbl [3 x 1]>
# 5  0.66552642 -1.3328070 -1.53575954 <dbl [3 x 1]>
# 6 -0.41251920 -0.2056882  1.66537220 <dbl [3 x 1]>
# 7  0.48396052  0.3968486  0.16110407 <dbl [3 x 1]>
# 8  0.43035213 -0.6433268  1.61640228 <dbl [3 x 1]>
# 9  0.06747126 -1.0146385 -0.47824193 <dbl [3 x 1]>
#10  0.79916411 -1.2349901 -0.05151402 <dbl [3 x 1]>

如果元素不必是矩阵:

my_tibble %>% mutate(Port_Weights = Map(c, A_Vector, B_Vector, C_Vector))

这相当于(使用 data.table::transpose ):

my_tibble %>% mutate(Port_Weights = data.table::transpose(as.list(.)))