中位数：需要数字数据(Median : need numeric data)

中位数：需要数字数据(Median : need numeric data)

为什么常规子集化可能无效？ 我想从data.table中计算中位数：

> median(DT.UsersA3[,1]) Error in median.default(DT.UsersA3[, 1]) : need numeric data

它是数字，但：

> class(DT.UsersA3$Timedif) [1] "numeric"

随着虹膜数据框架的运行：

> median(iris[,3]) [1] 4.35

词汇子集也适用于...

> median(DT.UsersA3$Timedif) [1] 422.046

Why regular subsetting might not work? I wanted to calculate median from a data.table:

> median(DT.UsersA3[,1]) Error in median.default(DT.UsersA3[, 1]) : need numeric data

it is numeric though:

> class(DT.UsersA3$Timedif) [1] "numeric"

With iris data frame it works:

> median(iris[,3]) [1] 4.35

And lexical subsetting also works...

> median(DT.UsersA3$Timedif) [1] 422.046

最满意答案

这是iris的例子：

library(data.table) Iris <- data.table(iris) median(Iris[,1]) # Error in median.default(Iris[, 1]) : need numeric data Iris[,1] # is a data.table Iris[,Sepal.Length] # is a vector

要使用列的编号，您可以按照Dason的评论：

Iris[[1]] # would return a vector median(Iris[[1]]) # works

Here is the example with iris:

library(data.table) Iris <- data.table(iris) median(Iris[,1]) # Error in median.default(Iris[, 1]) : need numeric data Iris[,1] # is a data.table Iris[,Sepal.Length] # is a vector

To use the number of the column you can follow the comment from Dason:

Iris[[1]] # would return a vector median(Iris[[1]]) # works