R 中的矩阵变换 - 从聚合输出到类外矩阵

Question

我需要将聚合（均值）的输出转换为类似于矩阵 outer 的样式。

data(mtcars)
aggregate(disp ~ cyl + gear, data = mtcars, FUN = mean )

  cyl gear     disp
  4    3 120.1000
  6    3 241.5000
  8    3 357.6167
  4    4 102.6250
  6    4 163.8000
  4    5 107.7000
  6    5 145.0000
  8    5 326.0000

我需要的是将 disp 的方法放入一个列为齿轮，行为圆柱体的矩阵中

像这样

    3   4   5
4 120 102 107
6 241 163 145
8 357 NA 326

你对我如何进行这种转变有什么建议吗？

有没有办法使用函数

outer

？

structure(list(mpg = c(21, 21, 22.8, 21.4, 18.7, 18.1, 14.3, 
24.4, 22.8, 19.2, 17.8, 16.4, 17.3, 15.2, 10.4, 10.4, 14.7, 32.4, 
30.4, 33.9, 21.5, 15.5, 15.2, 13.3, 19.2, 27.3, 26, 30.4, 15.8, 
19.7, 15, 21.4), cyl = c(6, 6, 4, 6, 8, 6, 8, 4, 4, 6, 6, 8, 
8, 8, 8, 8, 8, 4, 4, 4, 4, 8, 8, 8, 8, 4, 4, 4, 8, 6, 8, 4), 
disp = c(160, 160, 108, 258, 360, 225, 360, 146.7, 140.8, 
167.6, 167.6, 275.8, 275.8, 275.8, 472, 460, 440, 78.7, 75.7, 
71.1, 120.1, 318, 304, 350, 400, 79, 120.3, 95.1, 351, 145, 
301, 121), hp = c(110, 110, 93, 110, 175, 105, 245, 62, 95, 
123, 123, 180, 180, 180, 205, 215, 230, 66, 52, 65, 97, 150, 
150, 245, 175, 66, 91, 113, 264, 175, 335, 109), drat = c(3.9, 
3.9, 3.85, 3.08, 3.15, 2.76, 3.21, 3.69, 3.92, 3.92, 3.92, 
3.07, 3.07, 3.07, 2.93, 3, 3.23, 4.08, 4.93, 4.22, 3.7, 2.76, 
3.15, 3.73, 3.08, 4.08, 4.43, 3.77, 4.22, 3.62, 3.54, 4.11
), wt = c(2.62, 2.875, 2.32, 3.215, 3.44, 3.46, 3.57, 3.19, 
3.15, 3.44, 3.44, 4.07, 3.73, 3.78, 5.25, 5.424, 5.345, 2.2, 
1.615, 1.835, 2.465, 3.52, 3.435, 3.84, 3.845, 1.935, 2.14, 
1.513, 3.17, 2.77, 3.57, 2.78), qsec = c(16.46, 17.02, 18.61, 
19.44, 17.02, 20.22, 15.84, 20, 22.9, 18.3, 18.9, 17.4, 17.6, 
18, 17.98, 17.82, 17.42, 19.47, 18.52, 19.9, 20.01, 16.87, 
17.3, 15.41, 17.05, 18.9, 16.7, 16.9, 14.5, 15.5, 14.6, 18.6
), vs = c(0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 
0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1), am = c(1, 
1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 
0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1), gear = c(4, 4, 4, 3, 
3, 3, 3, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 4, 4, 4, 3, 3, 3, 
3, 3, 4, 5, 5, 5, 5, 5, 4), carb = c(4, 4, 1, 1, 2, 1, 4, 
2, 2, 4, 4, 3, 3, 3, 4, 4, 4, 1, 2, 1, 1, 2, 2, 4, 2, 1, 
2, 2, 4, 6, 8, 2)), .Names = c("mpg", "cyl", "disp", "hp", 
"drat", "wt", "qsec", "vs", "am", "gear", "carb"), row.names = c("Mazda RX4", 
"Mazda RX4 Wag", "Datsun 710", "Hornet 4 Drive", "Hornet Sportabout", 
"Valiant", "Duster 360", "Merc 240D", "Merc 230", "Merc 280", 
"Merc 280C", "Merc 450SE", "Merc 450SL", "Merc 450SLC", "Cadillac Fleetwood", 
"Lincoln Continental", "Chrysler Imperial", "Fiat 128", "Honda Civic", 
"Toyota Corolla", "Toyota Corona", "Dodge Challenger", "AMC Javelin", 
"Camaro Z28", "Pontiac Firebird", "Fiat X1-9", "Porsche 914-2", 
"Lotus Europa", "Ford Pantera L", "Ferrari Dino", "Maserati Bora", 
"Volvo 142E"), class = "data.frame")

Answer 1

你可以试试tapply

with(mtcars, tapply(disp, list(cyl, gear), FUN=mean))
#       3       4     5
#4 120.1000 102.625 107.7
#6 241.5000 163.800 145.0
#8 357.6167      NA 326.0

如果您正在寻找 reshape aggregate 的输出，我们可以使用 reshape2

的 acast

d1 <- aggregate(disp ~ cyl + gear, data = mtcars, FUN = mean )
acast(d1, cyl~gear, value.var='disp')

R 中的矩阵变换 - 从聚合输出到类外矩阵

Matrix Transformation in R - from aggregate output to outer-like matrix

r

matrix

aggregate

transformation

outer-join