r - Purrr 映射到拆分的数据帧上以获得每个组的 AUROC

Question

我已经在这里问过这个问题 ( Purrr map over splitted training-dataframe to get auroc for each model )，但数据真的很糟糕，这个问题可能有点令人困惑。另外我找到了解决这个问题的方法，但感觉不是一个好方法。

所以问题如下。我根据 geology 列拆分数据框。然后，我想使用训练数据框中的其他两列来预测列 trigger 。我想为每个地质学(列表的每个元素 - 数据框)执行此操作。然后我想在新的测试数据帧上预测这个模型并计算每个地质的 AUROC。

这是训练数据:

# the training data
structure(list(p3 = c(5, 0, 0, 2, 0, 0, 0, 2.8999999165535, 0, 
0, 0, 0, 17.5999999046326, 0, 0, 0.899999976158142, 10.0000000149012, 
1.79999995231628, 0, 8.80000019073486, 0, 0, 11.8999999761581, 
0, 9.60000026226044, 5.19999980926514, 11.7000002861023, 20.0999999046326, 
34.6000008583069, 0, 8.70000028610229, 33.8000000119209, 2.40000009536743, 
17, 27, 36.7999992370605, 0, 15.8999997973442, 0.300000011920929, 
7.69999980926514, 0, 0.899999976158142, 1.5, 0.300000011920929, 
3.50000002980232, 51.3999991416931, 6.09999990463257, 0.400000005960464, 
22, 65.3000020980835), p15 = c(34.2999999374151, 10.4999997392297, 
8.30000010877848, 69.4999992623925, 1.30000001192093, 0, 62.3999992161989, 
71.8999995738268, 32.6999994888902, 4, 0, 0.400000005960464, 
35.699999935925, 24.1000001206994, 0, 53.8999998271465, 41.8999992236495, 
37.8999994322658, 24.0999998524785, 65.5999999046326, 0, 0, 20.5000002905726, 
75.4000002145767, 68.1999989748001, 45.9000007808208, 180.999998480082, 
70.5000009462237, 112.099999666214, 11.3000001907349, 88.0999987274408, 
103.499998867512, 100.399998664856, 59.9999995827675, 200.699998855591, 
21.2999993562698, 47.1999997496605, 42.1999989748001, 58.6000000834465, 
161.299998879433, 43.3999999314547, 110.899999141693, 73.9000004529953, 
46.7999998703599, 25.7999995350838, 21.1000004559755, 86.100000500679, 
15.8999998569489, 5.3999999538064, 143.399998903275), trigger = c(FALSE, 
FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, 
FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, 
FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, TRUE, TRUE, TRUE, TRUE, 
TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, 
TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE), 
    geology = c("Sedimentary rocks", "Crystalline basement", 
    "Sedimentary rocks", "Sedimentary rocks", "Porphyry", "Porphyry", 
    "Porphyry", "Sedimentary rocks", "Sedimentary rocks", "Crystalline basement", 
    "Calcschists with ophiolites", "Crystalline basement", "Crystalline basement", 
    "Sedimentary rocks", "Porphyry", "Porphyry", "Crystalline basement", 
    "Crystalline basement", "Sedimentary rocks", "Crystalline basement", 
    "Sedimentary rocks", "Porphyry", "Crystalline basement", 
    "Crystalline basement", "Crystalline basement", "Crystalline basement", 
    "Sedimentary rocks", "Porphyry", "Sedimentary rocks", "Crystalline basement", 
    "Crystalline basement", "Crystalline basement", "Porphyry", 
    "Calcschists with ophiolites", "Crystalline basement", "Crystalline basement", 
    "Sedimentary rocks", "Porphyry", "Crystalline basement", 
    "Porphyry", "Crystalline basement", "Crystalline basement", 
    "Crystalline basement", "Crystalline basement", "Calcschists with ophiolites", 
    "Plutonite", "Crystalline basement", "Crystalline basement", 
    "Porphyry", "Sedimentary rocks")), row.names = c(NA, -50L
), class = c("tbl_df", "tbl", "data.frame"))

这里是测试数据

structure(list(p3 = c(6.40000009536743, 0, 0, 16.3000003397465, 
0, 0, 0, 0, 1, 1.5, 29.1000003814697, 7.49999982118607, 3.5, 
18.3999996185303, 2.69999990612268, 11.3000001907349, 0, 2, 9.5, 
0, 10.1999998092651, 0, 3.60000005364418, 0, 5.29999995231628, 
112.599998474121, 118.099997758865, 54.8999996185303, 72.8000011444092, 
79.9000015258789, 88.7000015377998, 0, 54.6000022888184, 144.599998474121, 
111.200000762939, 7.10000009834766, 32.0999999046326, 0.5, 5.3999999165535, 
0.300000011920929, 0, 36.7999982833862, 101.599998474121, 121.699998855591, 
31.0999994277954, 66.8000020980835, 139.200000762939, 9.50000011920929, 
135.300003051758, 110.900001525879), p15 = c(12.3999996185303, 
63.8000009655952, 20.7000007629395, 121.299998179078, 10.4000001549721, 
27.1999999880791, 49.5000003874302, 13.3000001907349, 31.3999998569489, 
15.4000002890825, 64.3999997377396, 25.1000001430511, 43.6999994516373, 
50.799999833107, 35.1999998092651, 35.1999998837709, 67.1000003442168, 
19.400000333786, 49.300000667572, 21.3999996706843, 75.600000411272, 
38.700000859797, 30.2999994754791, 14.9000003933907, 53.2000011727214, 
137.900000333786, 0.100000001490116, 119.300001859665, 139.700000107288, 
147.799997329712, 45.3000004068017, 56.5000000670552, 47.7999995946884, 
2.90000009536743, 139.499999403954, 26.6999999284744, 6.5, 149.700001835823, 
210.299998342991, 114.499999642372, 3.60000002384186, 60.099999524653, 
97.5999984890223, 153.100000120699, 245.299996376038, 123.49999922514, 
3.70000004768372, 90.5999985486269, 49.1000001132488, 138.599999785423
), trigger = c(FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, 
FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, 
FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, 
TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, 
TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, TRUE, 
TRUE, TRUE, TRUE)), row.names = c(NA, -50L), groups = structure(list(
    trigger = c(FALSE, TRUE), .rows = structure(list(1:25, 26:50), ptype = integer(0), class = c("vctrs_list_of", 
    "vctrs_vctr", "list"))), row.names = c(NA, -2L), class = c("tbl_df", 
"tbl", "data.frame"), .drop = TRUE), class = c("grouped_df", 
"tbl_df", "tbl", "data.frame"))

我现在为每个地质学拟合逻辑回归模型 trigger ~ p3 + 15 并获取每个类的 auroc 所做的工作如下:

res = train %>% split(., .$geology) %>%
  map( ~ glm(trigger ~ p3 + p15, data = .x, family = "binomial")) %>%
  map( ~ predict(.x, newdata = test, type = "response")) %>%
  map(function(x) {
    df = data.frame(ref = test$trigger)
    df[["pred"]] = x
    df
  }) %>% map_dfr(function(x) {
   auc = as.numeric(roc(ref ~ pred, data = x)$auc)
  }) %>% pivot_longer(cols = everything(), names_to = "geology", values_to="auc")

但有些部分(function(x){...})我想用更简洁的 purrr 风格的语法替换。我在思考 .x、. 以及何时使用 {} 来防止结果传入时遇到了一些麻烦小标题(在某些时候可能是必要的)。那么我怎样才能获得相同的结果，但是省略了 function(x) 语法呢？

Answer 1

您可以使用 group_by 和 summarise 而不是使用 split()。起初列表列使用起来有点棘手，但一旦你习惯了它们，它们在很多情况下都非常有用。我会尝试这样的事情:

library(tidyverse)

train %>% 
  group_by(geology) %>% 
  summarise(
    model = list(glm(trigger ~ p3 + p15, data = cur_data(), family = "binomial")),
    yhat = map(model, ~predict(.x, newdata = test, type = "response")),
    auc = map_dbl(yhat, ~pROC::roc(test$trigger, .x)$auc)
  ) %>% 
  select(geology, auc)

## A tibble: 5 x 2
#  geology                       auc
#  <chr>                       <dbl>
# 1 Calcschists with ophiolites 0.794
# 2 Crystalline basement        0.84 
# 3 Plutonite                   0.5  
# 4 Porphyry                    0.864
# 5 Sedimentary rocks           0.912

或者不创建临时列

train %>% 
  group_by(geology) %>% 
  summarise(
    auc = glm(trigger ~ p3 + p15, data = cur_data(), family = "binomial") %>% 
      predict(newdata = test, type = "response") %>% 
      pROC::roc(test$trigger, .) %>% `$`("auc") %>% as.numeric()
  )

^{由 reprex package 创建于 2021-06-28 (v1.0.0)}