Question

test = data.frame(a=factor(c("A","A","B","B","C","C")),
                  b=c(101,103,50,100,50,60),
                  c=factor(c("John","Mary","John","Mary","John","Mary"))) %>%
  group_by(c) %>% mutate(d=scale(b))
View(test)

为什么在FUN（X [[i]]，...）中产生错误错误： dims [product 3]与对象的长度不匹配[6]

我试图在每个c级别中对b的值进行z分数（即＆＃34;每个主题＆＃34;）。

Answer 1

您在attributes列中收到d，R不知道如何查看这些内容。将scale包裹在as.numeric()中会删除这些属性。

library(dplyr)
test = data.frame(a=factor(c("A","A","B","B","C","C")),
                                    b=c(101,103,50,100,50,60),
                                    c=factor(c("John","Mary","John","Mary","John","Mary"))) %>%
    group_by(c) %>% 
    mutate(d = as.numeric(scale(b)))

View(test)

Answer 2

以下作品：

test = data.frame(a=factor(c("A","A","B","B","C","C")),
               b=c(101,103,50,100,50,60), 
             c=factor(c("John","Mary","John","Mary","John","Mary"))) %>% 
   group_by(c) %>% mutate(d=scale(b)[, 1])
View(test)

这是因为scales返回一个矩阵作为其值，上面的内容是该矩阵的第一列。

group_by，mutate和scale一起出错

2 个答案: