将Dataframe转换为矩阵,将一列保留为属性

Question

我有一个数据帧如下:

Destination    User     User_Price 
     A          a           5
     A          b           4
     B          c           6
     B          a           5
     C          b           4
     C          d           7

我想将其转换为一个矩阵,显示用户点击的目标,如下所示:

   User    User_Price    A    B    C    
    a          5         1    1    0
    b          4         1    0    1
    c          6         0    1    0
    d          7         0    0    1

Answer 1

dplyr和tidyr包的一种方法是:

library(dplyr)
library(tidyr)

count(foo, User, User_Price, Destination) %>%
spread(key = Destination, value = n, fill = 0)

#    User User_Price     A     B     C
#  (fctr)      (int) (dbl) (dbl) (dbl)
#1      a          5     1     1     0
#2      b          4     1     0     1
#3      c          6     0     1     0
#4      d          7     0     0     1

如果需要矩阵,可以将此结果(数据框)转换为矩阵.

数据

foo <- structure(list(Destination = structure(c(1L, 1L, 2L, 2L, 3L, 
3L), .Label = c("A", "B", "C"), class = "factor"), User = structure(c(1L, 
2L, 3L, 1L, 2L, 4L), .Label = c("a", "b", "c", "d"), class = "factor"), 
User_Price = c(5L, 4L, 6L, 5L, 4L, 7L)), .Names = c("Destination", 
"User", "User_Price"), class = "data.frame", row.names = c(NA, 
-6L))