1

这是一段代码:

data <- data.frame(a=runif(20),b=runif(20),subject=rep(1:2,10)) %>%
group_by(subject) %>%
do(distance = dist(.))

#no dplyr
intermediate <- lapply(data$distance,as.matrix)
mean.dists <- apply(simplify2array(intermediate),MARGIN = c(1,2),FUN=mean)

#dplyr
mean.dists <- lapply(data$distance,as.matrix) %>%
apply(simplify2array(.),MARGIN=c(1,2),FUN=mean)

为什么“no dplyr”版本有效,而“dplyr”版本抛出错误,“dim(X) must have a positive length”?他们似乎和我一模一样。

4

1 回答 1

3

问题是您还没有完全实现管道。你在magrittr这里使用,和问题关系不大dplyr

data$distance %>% 
   lapply(as.matrix ) %>% 
   simplify2array %>% 
   apply(MARGIN=1:2, FUN=mean)
于 2015-02-20T03:01:33.023 回答