该代码使用每周计算的回归线绘制数据。 我想将图例与每周加倍时间结合起来，该时间是根据每周的坡度计算的。
很好解决问题：我可以通过geom_smooth获得每周回归线。
但是，我无法从geom_smooth中提取斜率系数（以计算倍增时间）。因此，我不得不在ggplot部分之外进行等效回归。
有什么建议可以更优雅地做到这一点吗？
主要问题：如何将图例与计算的倍增时间列结合？ 摆弄很多东西，我可以将图例放在这些计算的倍增时间旁边。 它看起来不太好，当我包含另一个数据点时，我必须再次重新摆弄。建议将不胜感激。谢谢。
library(ggplot2)
library(gridExtra)
# Input data: Daily number of cases starting at day0
cases <- c(1,1,2,3,7,10,13,16,24,38,51,62,85,116,150,202,240,274,402,554,709,927)
day0 <- as.Date("2020-03-04")
# actual dates by counting from day0
dates <- day0 + 1:length(cases)
# week number as factor to obtain regression line for each week
week <- as.factor(1 + (1:length(cases) ) %/% 7)
# tibble with daily data,also with week number
datatib <- tibble( dates,cases,week)
# tibble with computed doubling time per week
resulttib <- tibble(Week=unique(week),Doubling_Time=NA)
# linear regression on log of dependent variable
for (wk in unique(week) ) {
resulttib[wk,'Doubling_Time'] <-
round( log(2) / lm(log(cases) ~ dates,data=datatib[week==wk,] )$coef['dates'],2 )
}
# insert row at top for second line of column heading
resulttib <- add_row(resulttib,Week = '',Doubling_Time = '(days)',.before = 1)
doublingtime = tableGrob(resulttib[,'Doubling_Time'],rows=NULL)
gp <-
ggplot(datatib,aes(dates,color = week ) ) +
geom_point() +
geom_smooth( method = "lm",se = FALSE) +
scale_x_date() +
scale_y_continuous(trans="log10") +
labs(x = "",y = "Number of Cases") +
ggtitle("Number of Cases with Weekly Doubling Times") +
theme(plot.title = element_text(hjust = 0.5)) +
theme(legend.position=c(0.75,0),legend.justification=c(1.2,-0.1),legend.text=element_text(size=14) ) +
annotation_custom( doublingtime,xmin=dates[length(cases)]-2,xmax=dates[length(cases)],ymin=-2.65 )
