ggplot geom_smooth 对象中最陡峭的回归线的颜色代码

Colour code most steep regression lines in ggplot geom_smooth object

对于重复测量的项目,我得到了以下有关年龄和连续结果的数据:

library(ggplot2)
library(magrittr)

mydata <- 
  structure(
    list(ID = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 
                          3L, 3L, 3L, 3L, 3L, 4L, 4L, 5L, 5L, 5L, 6L, 6L, 6L, 6L, 6L, 7L, 
                          7L, 7L, 7L, 7L, 8L, 8L, 9L, 9L, 10L, 10L, 11L, 11L, 11L, 11L, 
                          12L, 12L, 13L, 13L, 14L, 14L, 14L, 14L, 14L, 15L, 15L, 16L, 16L, 
                          17L, 17L, 17L, 17L, 17L, 18L, 18L, 19L, 19L, 20L, 20L, 21L, 21L, 
                          22L, 22L, 22L, 22L, 22L, 23L, 23L, 24L, 24L, 24L, 24L), 
                        .Label = c("2", "3", "4", "7", "8", "13", "14", "20", "21", "22", "24", "25", "27", "29", "30", "31", "34", "36", "37", "38", "39", "40", "48", 
                                   "49", "50", "51", "52", "54", "58", "60", "61", "65", "74", "75", 
                                   "76", "77", "80", "81", "82", "83", "84", "86", "87", "88", "92", 
                                   "94", "95", "96", "103", "104", "105", "114", "115", "116", "117", 
                                   "119", "125", "126", "127", "132", "134", "135", "137", "138", 
                                   "141", "142", "145", "152", "153", "154", "157", "159", "160", 
                                   "162", "164", "165", "171", "172", "179", "180", "184", "185", 
                                   "189", "194", "195", "197", "198", "202", "203", "205", "209", 
                                   "213", "221", "253", "255", "258", "262", "271", "273", "277", 
                                   "279", "310", "315", "320"), class = "factor"), 
         date_ct = structure(c(15923, 16122, 16715, 16902, 17086, 18003, 16150, 16841, 16421, 16764, 
                               16951, 17135, 18011, 16622, 18247, 16582, 16752, 18045, 16729, 
                               16862, 17042, 17226, 18102, 16568, 16736, 16916, 17100, 18040, 
                               16743, 16841, 16589, 16729, 16526, 16729, 16619, 16862, 17042, 
                               17226, 16407, 18437, 16512, 16953, 16457, 16946, 17112, 17310, 
                               17989, 16573, 16841, 15923, 16752, 16505, 16729, 16909, 17107, 
                               18038, 16540, 16743, 15951, 16122, 16624, 18202, 16623, 18221, 
                               16694, 16715, 16902, 17086, 18037, 16451, 16743, 16421, 16736, 
                               16909, 17100), class = "Date"), 
         age = c(56.6, 57.1, 58.8, 59.3, 59.8, 62.3, 43.2, 45.1, 52, 52.9, 53.4, 53.9, 56.3, 58.5, 63, 
                 57.4, 57.9, 61.4, 57.8, 58.2, 58.7, 59.2, 61.6, 52.4, 52.8, 53.3, 
                 53.8, 56.4, 70.8, 71.1, 61.4, 61.8, 59.2, 59.8, 61.5, 62.2, 62.7, 
                 63.2, 48.9, 54.5, 54.2, 55.4, 50.1, 51.4, 51.8, 52.4, 54.3, 55.4, 
                 56.1, 48.6, 50.9, 64.2, 64.8, 65.3, 65.8, 68.4, 68.3, 68.8, 66.7, 
                 67.1, 60.5, 64.8, 56.5, 60.9, 62.7, 62.8, 63.3, 63.8, 66.4, 49, 
                 49.8, 61, 61.8, 62.3, 62.8), 
         continuous_outcome = c(1636.4, 544.1, 1408, 1594.7, 1719.4, 2345.9, 115.3, 226, 2678.2, 3451.6, 3702.7, 
                                3632.7, 5805, 155.2, 1095, 992.2, 296.6, 2020.4, 3708.6, 2710.7, 
                                2934.2, 3080.4, 4489.7, 3459.4, 4965.3, 5553.1, 5037.8, 7315.7, 
                                29980.8, 35407.5, 2263.2, 2060.6, 3220.7, 4467.1, 5902.3, 6407.2, 
                                5947.1, 6271.6, 306, 689.3, 1430.6, 1672.1, 9.9, 58.7, 69.9, 
                                125.3, 39.5, 3842.5, 5136.3, 216.6, 332.4, 5719.3, 5386, 5490.7, 
                                5268.2, 6166.7, 12520.6, 12981.8, 2896.1, 2976.8, 5495.6, 6470.6, 
                                4235.5, 7603.5, 3887, 3344.5, 2885.7, 3324.1, 6401, 1942.2, 2000.9, 
                                2401.7, 2231.5, 2749.7, 2741.7)), 
    row.names = c(NA, -75L), class = c("tbl_df", "tbl", "data.frame"))

我为每位患者绘制了如下线性回归线:

ggplot(mydata, aes(x=age, y=continuous_outcome, group=ID, color=factor(ID))) + 
  theme(legend.position = "none") + geom_smooth(method="lm", formula=y~x, se=FALSE, size=0.5)

我想用肉眼观察线条最陡峭的地方,所以例如让更陡峭的线条更红或更大等。有没有办法做到这一点?

谢谢!

可以,只需先为系数创建一个变量:

library(tidyverse)

mydata %>% 
  group_by(ID) %>% 
  mutate(beta = lm(continuous_outcome ~ age)$coef[2]) %>% 
  ggplot(aes(x = age, 
             y = continuous_outcome, 
             group = ID, 
             color = beta
             )
         ) + 
  geom_smooth(method="lm", formula=y~x, se=FALSE, size=0.5) 

注意:鉴于异常值较大,底部线条之间的颜色差异难以察觉。如果您的用例需要有明显的差异,您可能想要进行日志转换。选择其他色标也可能有所帮助。

编辑:

mydata %>% 
  group_by(ID) %>% 
  mutate(beta = lm(continuous_outcome ~ age)$coef[2]) %>% 
  ggplot(aes(x = age, 
             y = continuous_outcome, 
             group = ID, 
             color = beta
             )
         ) + 
  geom_smooth(method="lm", formula=y~x, se=FALSE) +
  scale_color_viridis_c(trans = "pseudo_log")


mydata %>% 
  group_by(ID) %>% 
  mutate(beta = lm(continuous_outcome ~ age)$coef[2]) %>% 
  ggplot(aes(x = age, 
             y = continuous_outcome, 
             group = ID, 
             size = beta
             )
         ) + 
  geom_smooth(method="lm", formula=y~x, se=FALSE)