如何使用dcast传播？

Question

我想用reshape2::dcast编写下面的tidyr::spread调用

stocks <- data.frame(
  time = as.Date('2009-01-01') + 0:9,
  X = rnorm(10, 0, 1),
  Y = rnorm(10, 0, 2),
  Z = rnorm(10, 0, 4)
)
stocksm <- stocks %>% gather(stock, price, -time)

stocksm %>% spread(time, price)

我弄不清楚要传递给fun.aggregate的是什么

Answer 1

您可以使用此方法：

library(reshape2)
dcast(stocksm, stock ~ time)