r - 在R中的多列上执行lm()和segmented()

Question

我正在尝试使用相同的自变量(x)和多个因响应变量(Curve1、Curve2等)一一执行R中的lm()和segmented()。我希望提取每个响应变量的估计断点和模型系数。我在下面提供了我的数据示例。

           x  Curve1  Curve2   Curve3
1  -0.236422 98.8169 95.6828 101.7910
2  -0.198083 98.3260 95.4185 101.5170
3  -0.121406 97.3442 94.8899 100.9690
4   0.875399 84.5815 88.0176  93.8424
5   0.913738 84.1139 87.7533  93.5683
6   1.795530 73.3582 78.1278  82.9956
7   1.833870 72.8905 77.7093  82.7039
8   1.872200 72.4229 77.3505  82.4123
9   2.907350 59.2070 67.6652  74.5374
10  3.865810 46.4807 58.5158  65.0220
11  3.904150 45.9716 58.1498  64.7121
12  3.942490 45.4626 57.8099  64.4022
13  4.939300 33.3040 48.9742  56.3451
14  4.977640 32.9641 48.6344  56.0352
15  5.936100 24.4682 36.4758  47.0485
16  5.936100 24.4682 36.4758  47.0485
17  6.012780 23.7885 35.9667  46.5002
18  6.971250 20.7387 29.6035  39.6476
19  7.009580 20.6167 29.3490  39.3930
20  8.006390 18.7209 22.7313  32.7753
21  8.121410 18.5022 22.3914  32.1292
22  9.041530 16.4722 19.6728  26.9604
23  9.079870 16.3877 19.5595  26.7450

我可以使用下面的代码一次完成一条曲线。然而，我的完整数据集有超过 1000 条曲线，因此我希望能够以某种方式在每一列上重复此代码。我并没有成功地尝试在每一列上循环它，所以如果有人可以向我展示如何做类似的事情并创建一个类似于下面代码生成的摘要数据框，但包含每一列，我会非常感激。谢谢!

model <- lm(Curve1~x, dat) # Linear model
seg_model <- segmented(model, seg.Z = ~x) # Segmented model
breakpoint <- as.matrix(seg_model$psi.history[[5]]) # Extract breakpoint
coefficients <- as.matrix(seg_model$coefficients) # Extract coefficients
summary_curve1 <- as.data.frame(rbind(breakpoint, coefficients)) # combine breakpoint and coefficeints
colnames(summary_curve1) <- "Curve_1" # header name 
summary_curve1 # display summary

Answer 1

这是一种使用 tidyverse 和 broom 返回包含每个 Curve 列结果的数据帧的方法:

library(broom)
library(tidyverse)

model.results = setNames(names(dat[,-1]), names(dat[,-1])) %>% 
  map(~ lm(paste0(.x, " ~ x"), data=dat) %>% 
        segmented(seg.Z=~x) %>%
        list(model=tidy(.), 
             psi=data.frame(term="breakpoint", estimate=.[["psi.history"]][[5]]))) %>%
  map_df(~.[2:3] %>% bind_rows, .id="Curve")

model.results

    Curve        term   estimate  std.error   statistic      p.value
1  Curve1 (Intercept)  95.866127 0.14972382  640.286416 1.212599e-42
2  Curve1           x -12.691455 0.05220412 -243.112130 1.184191e-34
3  Curve1        U1.x  10.185816 0.11080880   91.922447 1.233602e-26
4  Curve1      psi1.x   0.000000 0.02821843    0.000000 1.000000e+00
5  Curve1  breakpoint   5.595706         NA          NA           NA
6  Curve2 (Intercept)  94.826309 0.45750667  207.267599 2.450058e-33
7  Curve2           x  -9.489342 0.11156425  -85.057193 5.372730e-26
8  Curve2        U1.x   6.532312 1.17332640    5.567344 2.275438e-05
9  Curve2      psi1.x   0.000000 0.23845241    0.000000 1.000000e+00
10 Curve2  breakpoint   7.412087         NA          NA           NA
11 Curve3 (Intercept) 100.027990 0.29453941  339.608175 2.069087e-37
12 Curve3           x  -8.931163 0.08154534 -109.523900 4.447569e-28
13 Curve3        U1.x   2.807215 0.36046013    7.787865 2.492325e-07
14 Curve3      psi1.x   0.000000 0.26319757    0.000000 1.000000e+00
15 Curve3  breakpoint   6.362132         NA          NA           NA