我很难弄清楚如何将purrr::map()
与mutate(across(...))
一起使用。
我想做一个线性模型,并得出由单个列预测的多个列的斜率的估计值。
以下是我尝试的一个示例数据集:
mtcars %>%
mutate(across(-mpg),
map(.x, lst(slope = ~lm(.x ~ mpg, data = .x) %>%
tidy() %>%
filter(term != "(Intercept") %>%
pull(estimate)
)))
我正在寻找的输出将是每个非mpg列的新列,名称后附加_slope,即cyl_slope
在我的实际数据中,我也将按另一个变量进行分组,以备不时之需,因为我需要每个预测变量的每组斜率。我在一个标准的变异中工作,一次做一个变量,如下所示:
df %>%
group_by(unitid) %>%
nest() %>%
mutate(tuition_and_fees_as_pct_total_rev_slope = map_dbl(data, ~lm(tuition_and_fees_as_pct_total_rev ~ year, data = .x) %>%
tidy() %>%
filter(term == "year") %>%
pull(estimate)
))
因此:
- 我认为我的问题是如何将预测的列名传递到
lm
- 我不知道该解决方案是否需要嵌套,所以如果在
mtcars
示例中考虑嵌套,我将不胜感激
如果我们想在自变量为"mpg"的所有其他列上执行lm
,一个选项是循环遍历"mtcars"(除了"mpg’(的列名,使用reformulate
创建公式,应用lm
,转换为tidy
格式,filter
输出"Intercept",select
输出"estimate"列
library(dplyr)
library(tidyr)
library(broom)
map_dfc(setdiff(names(mtcars), 'mpg'), ~
lm(reformulate('mpg', response = .x), data = mtcars) %>%
tidy %>%
filter(term != "(Intercept)") %>%
select(estimate))
-输出
# A tibble: 1 x 10
# estimate...1 estimate...2 estimate...3 estimate...4 estimate...5 estimate...6 estimate...7 estimate...8 estimate...9 estimate...10
# <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
#1 -0.253 -17.4 -8.83 0.0604 -0.141 0.124 0.0555 0.0497 0.0588 -0.148
或者使用matrix
作为依赖可以更容易地完成
library(stringr)
lm(as.matrix(mtcars[setdiff(names(mtcars), "mpg")]) ~ mpg,
data = mtcars) %>%
tidy %>%
filter(term != "(Intercept)") %>%
select(response, estimate) %>%
mutate(response = str_c(response, '_slope'))
-输出
# A tibble: 10 x 2
# response estimate
# <chr> <dbl>
# 1 cyl_slope -0.253
# 2 disp_slope -17.4
# 3 hp_slope -8.83
# 4 drat_slope 0.0604
# 5 wt_slope -0.141
# 6 qsec_slope 0.124
# 7 vs_slope 0.0555
# 8 am_slope 0.0497
# 9 gear_slope 0.0588
#10 carb_slope -0.148
或者另一个选项是带有across
的summarise
mtcars %>%
summarise(across(-mpg, ~ list(lm(reformulate('mpg',
response = cur_column())) %>%
tidy %>%
filter(term != "(Intercept)") %>%
pull(estimate)), .names = "{.col}_slope")) %>%
unnest(everything())
# A tibble: 1 x 10
# cyl_slope disp_slope hp_slope drat_slope wt_slope qsec_slope vs_slope am_slope gear_slope carb_slope
# <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl> <dbl>
#1 -0.253 -17.4 -8.83 0.0604 -0.141 0.124 0.0555 0.0497 0.0588 -0.148
一个选项可以是:
map_dfr(.x = names(select(mtcars, -c(mpg, vs))),
~ mtcars %>%
group_by(vs) %>%
nest() %>%
mutate(variable = .x,
estimate = map_dbl(data, function(y) lm(!!sym(.x) ~ mpg, data = y) %>%
tidy() %>%
filter(term != "(Intercept)") %>%
pull(estimate))) %>%
select(-data))
vs variable estimate
<dbl> <chr> <dbl>
1 0 cyl -0.242
2 1 cyl -0.116
3 0 disp -22.5
4 1 disp -8.01
5 0 hp -10.1
6 1 hp -3.26
7 0 drat 0.0748
8 1 drat 0.0529
9 0 wt -0.192
10 1 wt -0.113
11 0 qsec -0.0357
12 1 qsec -0.0432
13 0 am 0.0742
14 1 am 0.0710
15 0 gear 0.114
16 1 gear 0.0492
17 0 carb -0.0883
18 1 carb -0.0790