从嵌套的数据框/小标题运行多个简单的线性回归

问题描述

我试图基于嵌套数据框中的数据运行多个简单的线性回归，并使用tidy()将回归拟合系数存储在数据框中.我的代码块如下

I am trying to run multiple simple linear regressions based on data from a nested data frame and store the regression fit coefficients in a dataframe using tidy(). My code block is as follows

library(tidyverse)
library(broom)
library(reshape2)
library(dplyr)

Factors <- as.factor(c("A","B","C","D"))
set.seed(5)
DF <- data.frame(Factors, X = rnorm(4), Y = rnorm(4), Z= rnorm(4))
MDF <- melt(DF, id.vars=c("Factors","X"))
DFF <- MDF %>% nest(-Factors)

如果它是一个包含许多列的数据框，我可以使用以下方法进行多个简单的线性回归

If it is a single dataframe with many columns, I can do multiple simple linear regressions using

MDF %>% group_by(variable) %>% do(tidy(lm(value ~ X, data =.)))

或者如果它是一个嵌套的数据框，并且我必须运行一个简单的线性回归，我可以尝试

or if it is a nested dataframe and I have to run one simple linear regression, I can try

MDF %>% nest(-Factors)
%>% mutate(fit = map(data, ~lm(Y ~ X, data = .)), results = map(fit,tidy))
%>% unnest(results)

但是我需要做的是上述两种情况的结合.我需要从嵌套数据框中的数据运行多个简单的线性回归.

But What I need to do is a combination of both of the above cases. I need to run multiple simple linear regressions from data in nested dataframe.

推荐答案

您可以通过两个分组变量来嵌套:

You could nest by both grouping variables:

MDF %>% nest(-Factors, -variable) %>%
  mutate(fit = map(data, ~lm(value ~ X, data = .)),
         results = map(fit,tidy)) %>%
  unnest(results)

您还可以使用 split 并避免嵌套:

You could also use split and avoid nesting:

split(MDF, list(MDF$Factors, MDF$variable)) %>%
  map_df(~ tidy(lm(value ~ X, data=.x)) %>%
           mutate(Factors=.x$Factors[1],
                  variable=.x$variable[1]))

或者，如果您不介意单个列中的组标识符，则:

Or, if you don't mind the group identifiers in a single column:

split(MDF, list(MDF$Factors, MDF$variable), sep="_") %>%
  map_df(~ tidy(lm(value ~ X, data=.x)), .id="Factors_variable")

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