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Adding multiple vlines to facetted charts?

How to Adding multiple vlines to facetted charts

I'm trying to create plots of stock prices over time and add vertical lines at the ex-dates. The only thing giving me trouble now is getting multiple lines on the same chart for each stock.

For example I currently have data on 9 stocks and their ex-dates. I want to create 9 charts each one havings its own ex-dates marked off using vline.

Here is the head of the

> head(test)
  ticker   ref_date price_open price_high price_low price_close  volume price_adjusted ret_adjusted_prices
1    BTI 2023-01-25      37.66      38.15     37.66       38.09 2938600       34.92060        -0.003401351
2    BTI 2023-01-26      37.92      37.94     37.61       37.76 2668200       34.61806        -0.008663758
3    BTI 2023-03-21      36.72      36.79     36.48       36.65 2728300       33.60042         0.007698789
4    BTI 2023-03-22      36.72      36.80     36.19       36.19 3548300       33.17869        -0.012551332
5    BTI 2023-03-27      35.41      35.54     35.36       35.40 3923300       33.09549         0.004255342
6    BTI 2023-01-30      37.70      38.17     37.66       38.07 3399600       34.90226         0.013848386
  ret_closing_prices cumret_adjusted_prices                       Company Ex-Dividend Date Dividend
1       -0.003401388               1.147131 British American Tobacco ADR      Mar 21, 2024 0.733059
2       -0.008663739               1.137192 British American Tobacco ADR      Mar 21, 2024 0.733059
3        0.007698724               1.103763 British American Tobacco ADR      Mar 21, 2024 0.733059
4       -0.012551238               1.089909 British American Tobacco ADR      Mar 21, 2024 0.733059
5        0.004255362               1.087176 British American Tobacco ADR      Mar 21, 2024 0.733059
6        0.013848215               1.146528 British American Tobacco ADR      Mar 21, 2024 0.733059
     exdate1    exdate2    exdate3    exdate4    exdate5    exdate6    exdate7    exdate8    exdate9
1 2025-06-27 2025-03-21 2024-12-19 2024-09-26 2024-06-27 2024-03-21 2023-12-21 2023-09-28 2023-07-13
2 2025-06-27 2025-03-21 2024-12-19 2024-09-26 2024-06-27 2024-03-21 2023-12-21 2023-09-28 2023-07-13
3 2025-06-27 2025-03-21 2024-12-19 2024-09-26 2024-06-27 2024-03-21 2023-12-21 2023-09-28 2023-07-13
4 2025-06-27 2025-03-21 2024-12-19 2024-09-26 2024-06-27 2024-03-21 2023-12-21 2023-09-28 2023-07-13
5 2025-06-27 2025-03-21 2024-12-19 2024-09-26 2024-06-27 2024-03-21 2023-12-21 2023-09-28 2023-07-13
6 2025-06-27 2025-03-21 2024-12-19 2024-09-26 2024-06-27 2024-03-21 2023-12-21 2023-09-28 2023-07-13
    exdate10   exdate11   exdate12   exdate13   exdate14   exdate15 potential
1 2023-03-23 2022-12-22 2022-09-29 2022-07-07 2022-03-24 2021-12-22  1442.083
2 2023-03-23 2022-12-22 2022-09-29 2022-07-07 2022-03-24 2021-12-22  1442.083
3 2023-03-23 2022-12-22 2022-09-29 2022-07-07 2022-03-24 2021-12-22  1442.083
4 2023-03-23 2022-12-22 2022-09-29 2022-07-07 2022-03-24 2021-12-22  1442.083
5 2023-03-23 2022-12-22 2022-09-29 2022-07-07 2022-03-24 2021-12-22  1442.083
6 2023-03-23 2022-12-22 2022-09-29 2022-07-07 2022-03-24 2021-12-22  1442.083

currently I've tried

charts <- ggplot(data=test, aes(x = ref_date, y = price_close))
charts <- charts + geom_line()+geom_vline(xintercept=c(test[,16]),color='red')
charts <- charts + facet_wrap(~ticker, scales = 'free') 
print(charts)

which gives me chart produced

but if i try

charts <- ggplot(data=test, aes(x = ref_date, y = price_close))
charts <- charts + geom_line()+geom_vline(xintercept=c(test[,16:29]),color='red')
charts <- charts + facet_wrap(~ticker, scales = 'free') 
print(charts)

I get the following error:

Error in geom_vline(): ! Problem while converting geom to grob. ℹ Error occurred in the 2nd layer. Caused by error in UseMethod(): ! no applicable method for 'rescale' applied to an object of class "list" Run rlang::last_trace() to see where the error occurred.

Solution:

The issue is that in your second approach you pass a data.frame to xintercept which results in an error.

Instead, to achieve your desired result create a separate data frame containing the dates for the vlines by ticker:

library(ggplot2)
library(tidyr)
library(dplyr, warn = FALSE)

dat_vline <- test |>
  dplyr::select(ticker, dplyr::starts_with("exdate")) |>
  tidyr::pivot_longer(-ticker, names_to = "exdate") |>
  # Keep only the distinct dates per ticker
  dplyr::distinct(ticker, value)

ggplot(test, aes(ref_date, price_close)) +
  geom_line() +
  geom_vline(
    data = dat_vline,
    aes(xintercept = value),
    color = "red"
  ) +
  # Just for the reprex
  scale_x_date(
    limits = range(dat_vline$value)
  ) +
  #
  facet_wrap(~ticker, scales = "free")

DATA

test <- data.frame(
  ticker = c("BTI", "BTI", "BTI", "BTI", "BTI", "BTI"),
  ref_date = as.Date(c("2023-01-25", "2023-01-26", "2023-03-21", "2023-03-22", "2023-03-27", "2023-01-30")),
  price_open = c(37.66, 37.92, 36.72, 36.72, 35.41, 37.70),
  price_high = c(38.15, 37.94, 36.79, 36.80, 35.54, 38.17),
  price_low = c(37.66, 37.61, 36.48, 36.19, 35.36, 37.66),
  price_close = c(38.09, 37.76, 36.65, 36.19, 35.40, 38.07),
  volume = c(2938600, 2668200, 2728300, 3548300, 3923300, 3399600),
  price_adjusted = c(34.92060, 34.61806, 33.60042, 33.17869, 33.09549, 34.90226),
  ret_adjusted_prices = c(-0.003401351, -0.008663758, 0.007698789, -0.012551332, 0.004255342, 0.013848386),
  ret_closing_prices = c(-0.003401388, -0.008663739, 0.007698724, -0.012551238, 0.004255362, 0.013848215),
  cumret_adjusted_prices = c(1.147131, 1.137192, 1.103763, 1.089909, 1.087176, 1.146528),
  Company = c("British American Tobacco ADR", "British American Tobacco ADR", "British American Tobacco ADR", "British American Tobacco ADR", "British American Tobacco ADR", "British American Tobacco ADR"),
  `Ex-Dividend Date` = as.Date(c("2024-03-21", "2024-03-21", "2024-03-21", "2024-03-21", "2024-03-21", "2024-03-21")),
  Dividend = c(0.733059, 0.733059, 0.733059, 0.733059, 0.733059, 0.733059),
  exdate1 = as.Date("2025-06-27"),
  exdate2 = as.Date("2025-03-21"),
  exdate3 = as.Date("2024-12-19"),
  exdate4 = as.Date("2024-09-26"),
  exdate5 = as.Date("2024-06-27"),
  exdate6 = as.Date("2024-03-21"),
  exdate7 = as.Date("2023-12-21"),
  exdate8 = as.Date("2023-09-28"),
  exdate9 = as.Date("2023-07-13"),
  exdate10 = as.Date("2023-03-23"),
  exdate11 = as.Date("2022-12-22"),
  exdate12 = as.Date("2022-09-29"),
  exdate13 = as.Date("2022-07-07"),
  exdate14 = as.Date("2022-03-24"),
  exdate15 = as.Date("2021-12-22"),
  potential = c(1442.083, 1442.083, 1442.083, 1442.083, 1442.083, 1442.083)
)