R 如何将多个变量的重复测量值传播为宽格式

我试图将长格式的专栏扩展到宽格式，如下所示.我想用tidyr来解决我正在投资的数据处理工具的问题，但为了让这个答案更一般，请提供其他解决方案.

以下是我所拥有的:

library(dplyr); library(tidyr)

set.seed(10)
dat <- data_frame(
    Person = rep(c("greg", "sally", "sue"), each=2),
    Time = rep(c("Pre", "Post"), 3),
    Score1 = round(rnorm(6, mean = 80, sd=4), 0),
    Score2 = round(jitter(Score1, 15), 0),
    Score3 = 5 + (Score1 + Score2)/2
)

##   Person Time Score1 Score2 Score3
## 1   greg  Pre     80     78   84.0
## 2   greg Post     79     80   84.5
## 3  sally  Pre     75     74   79.5
## 4  sally Post     78     78   83.0
## 5    sue  Pre     81     78   84.5
## 6    sue Post     82     81   86.5

所需的宽幅格式:

  Person Pre.Score1 Pre.Score2 Pre.Score3  Post.Score1 Post.Score2 Post.Score3
1   greg         80         78       84.0           79          80        84.5
2  sally         75         74       79.5           78          78        83.0
3    sue         81         78       84.5           82          81        86.5

我可以通过 for each 分数做这样的事情:

spread(dat %>% select(Person, Time, Score1), Time, Score1) %>% 
    rename(Score1_Pre = Pre, Score1_Post = Post)

然后使用_join，但这似乎很冗长，而且肯定有更好的方法.

Related questions:
tidyr wide to long with two repeated measures
Is it possible to use spread on multiple columns in tidyr similar to dcast?