在R语言绘图中添加2020、2022年初垂直竖线的问题排查

问题说明 #

我需要在R绘制的折线图中，给2020年和2022年年初添加垂直竖线，但怀疑日期格式不匹配导致竖线无法正常显示。

我的数据 #

dput(plot_data2)
structure(list(Date = structure(c(1640995200, 1648771200, 1656633600, 
1664582400, 1672531200, 1680307200, 1688169600), tzone = "UTC", class = c("POSIXct", 
"POSIXt")), Index = c(1.159, 1.19, 1.2, 1.203, 1.203, 1.212, 
1.218), Compensation = c(0.667, 0.674, 0.682, 0.685, 0.694, 0.702, 
0.704), Depreciation = c(0.174, 0.178, 0.181, 0.184, 0.186, 0.189, 
0.189), Taxes = c(0.107, 0.11, 0.109, 0.109, 0.11, 0.109, 0.109
), Interest = c(0.027, 0.026, 0.025, 0.023, 0.022, 0.019, 0.015
), Corpotaxes = c(0.038, 0.038, 0.036, 0.037, 0.038, 0.038, 0.038
), Profits = c(0.147, 0.165, 0.167, 0.164, 0.153, 0.156, 0.162
), Profitshare = c(0.125970664365833, 0.13781512605042, 0.139166666666667, 
0.13715710723192, 0.127182044887781, 0.127887788778878, 0.133825944170772
), InterestTaxesCounter = c(0.13, 0.143, 0.142, 0.142, 0.143, 
0.142, 0.142), Counterfactual = c(0.129421915444349, 0.131932773109244, 
0.1325, 0.12884455527847, 0.118038237738986, 0.116336633663366, 
0.119047619047619)), row.names = c(NA, -7L), class = c("tbl_df", 
"tbl", "data.frame"))

当前尝试的代码 #

plot_data2 <- 
  subset(indexprofitshare, Date >= as.Date("2018-01-01"))

plot(plot_data2$Date, plot_data2$Profitshare,
     type = "l", yaxt = "n", col = "blue",
     xlab = "Date", ylab = "Value", ylim = c(0.05, 0.15)
  )

lines(
  indexprofitshare$Date[indexprofitshare$Date >= as.Date("2020-01-01")],
  indexprofitshare$Counterfactual[indexprofitshare$Date >= as.Date("2020-01-01")],
  type = "l", col = "red", lty = 2
  )

legend("bottomright",
       legend = c("Profitshare", "Counterfactual"),
       col = c("blue", "red"), lty = c(1, 2)
  )

axis(side = 2, at = pretty(c(0.06,0.14)), 
     labels = paste0(pretty(c(0.06,0.14) * 100), '%'),
     las = 1
  )

abline(v = c(as.Date("2022-01-01"), as.Date("2022-01-01")), 
       col = c("blue", "red"), lty = c(1,2), lwd = c(1, 3))

问题根源与修正方案 #

核心问题 #

1. 日期格式不匹配：数据中Date列是带UTC时区的POSIXct类型，但用as.Date()生成竖线日期，两者类型不兼容，导致竖线位置错误或不显示。
2. 竖线日期重复：abline里重复写了2022-01-01，未添加2020-01-01的竖线。
3. 数据范围限制：提供的数据最早日期是2022-01-01，默认x轴范围不包含2020年，竖线会显示在图表左侧之外。

修正后的完整代码 #

# 加载数据
plot_data2 <- structure(list(Date = structure(c(1640995200, 1648771200, 1656633600, 
1664582400, 1672531200, 1680307200, 1688169600), tzone = "UTC", class = c("POSIXct", 
"POSIXt")), Index = c(1.159, 1.19, 1.2, 1.203, 1.203, 1.212, 
1.218), Compensation = c(0.667, 0.674, 0.682, 0.685, 0.694, 0.702, 
0.704), Depreciation = c(0.174, 0.178, 0.181, 0.184, 0.186, 0.189, 
0.189), Taxes = c(0.107, 0.11, 0.109, 0.109, 0.11, 0.109, 0.109
), Interest = c(0.027, 0.026, 0.025, 0.023, 0.022, 0.019, 0.015
), Corpotaxes = c(0.038, 0.038, 0.036, 0.037, 0.038, 0.038, 0.038
), Profits = c(0.147, 0.165, 0.167, 0.164, 0.153, 0.156, 0.162
), Profitshare = c(0.125970664365833, 0.13781512605042, 0.139166666666667, 
0.13715710723192, 0.127182044887781, 0.127887788778878, 0.133825944170772
), InterestTaxesCounter = c(0.13, 0.143, 0.142, 0.142, 0.143, 
0.142, 0.142), Counterfactual = c(0.129421915444349, 0.131932773109244, 
0.1325, 0.12884455527847, 0.118038237738986, 0.116336633663366, 
0.119047619047619)), row.names = c(NA, -7L), class = c("tbl_df", 
"tbl", "data.frame"))

# 绘制图表，扩展x轴范围以显示2020年的竖线
plot(plot_data2$Date, plot_data2$Profitshare,
     type = "l", yaxt = "n", col = "blue",
     xlab = "日期", ylab = "数值", ylim = c(0.05, 0.15),
     xlim = c(as.POSIXct("2020-01-01", tz = "UTC"), max(plot_data2$Date))
  )

# 绘制反事实值折线，统一用POSIXct格式判断日期
lines(
  plot_data2$Date[plot_data2$Date >= as.POSIXct("2020-01-01", tz = "UTC")],
  plot_data2$Counterfactual[plot_data2$Date >= as.POSIXct("2020-01-01", tz = "UTC")],
  type = "l", col = "red", lty = 2
  )

# 添加图例
legend("bottomright",
       legend = c("利润份额", "反事实值"),
       col = c("blue", "red"), lty = c(1, 2)
  )

# 设置y轴刻度为百分比
axis(side = 2, at = pretty(c(0.06, 0.14)), 
     labels = paste0(pretty(c(0.06, 0.14)) * 100, '%'),
     las = 1
  )

# 生成匹配格式的竖线日期，添加垂直竖线
v_lines <- as.POSIXct(c("2020-01-01", "2022-01-01"), tz = "UTC")
abline(v = v_lines, 
       col = c("blue", "red"), lty = c(1, 2), lwd = c(1, 3))

关键修正点 #

• 所有日期判断和竖线日期都使用as.POSIXct()并指定tz="UTC"，确保和数据的日期类型、时区完全一致。
• 在plot()中添加xlim参数，扩展x轴左边界到2020年，让2020年的竖线能显示在图表内。
• 修正abline中的日期数组，包含2020-01-01和2022-01-01两个目标日期。

内容的提问来源于stack exchange，提问作者Ayoze Alfageme