将向量列表转换为数据框 [英] Convert list of vectors to data frame

问题描述

我正在尝试将向量列表(本质上是多维数组)转换为数据帧，但是每次尝试都得到意想不到的结果.

I'm trying to convert a list of vectors (a multidimensional array essentially) into a data frame, but every time I try I'm getting unexpected results.

我的目的是实例化一个空白列表，在for循环中填充包含有关该循环迭代信息的向量，然后在完成后将其转换为数据帧.

My aim is to instantiate a blank list, populate it in a for loop with vectors containing information about that iteration of the loop, then convert it into a data frame after it's finished.

> vectorList <- list()
> for(i in  1:5){
+     vectorList[[i]] <- c("number" = i, "square root" = sqrt(i))
+ }
> vectorList

输出:

> [[1]]
>      number square root 
>           1           1 
> 
> [[2]]
>      number square root 
>    2.000000    1.414214 
> 
> [[3]]
>      number square root 
>    3.000000    1.732051 
> 
> [[4]]
>      number square root 
>           4           2 
> 
> [[5]]
>      number square root 
>    5.000000    2.236068

现在我希望它成为具有2个变量的5个观察值的数据框，但是尝试从'vectorList'创建数据框

Now I want this to become a data frame with 5 observations of 2 variables, but trying to create a data frame from 'vectorList'

numbers <- data.frame(vectorList)

对5个变量进行2次观察.

results in 2 observations of 5 variables.

奇怪的是，它甚至不会被reshape2强制(我知道这很糟糕，但是我尝试过).

Weirdly it won't even be coerced with reshape2 (which I know would be an awful work around, but I tried).

任何人都有见识吗?

推荐答案

您可以使用:

as.data.frame(do.call(rbind, vectorList))

或者:

library(data.table)
rbindlist(lapply(vectorList, as.data.frame.list))

或者:

library(dplyr)
bind_rows(lapply(vectorList, as.data.frame.list))

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