R 带有嵌套x变量的两行上的轴标签（月份以下年份）

我想沿着横轴显示月份（缩写形式），相应的年份打印一次。我知道如何显示月份和年份：

联合国需要重复的一年，把标签弄得乱七八糟。相反，我想要这样的东西：

除了年度将打印在月份下方

我把年份打印在axis标签上，因为这是我能做的最好的了。这遵循了

annotate（）

函数的限制，如果它位于绘图区域之外，则会被剪裁。我知道基于

annotate_custom（）

的可能解决方法，但我无法使它们与日期对象一起工作（我没有尝试将日期转换为数字，然后再转换回日期，因为这似乎比希望的更复杂）

我想知道新的

dup\u axis（）

是否会因此被劫持。如果不将复制轴发送到面板的另一侧，而是可以在复制轴下方发送几行，那么可能只需要设置一个轴，其中

panel.grid.major

为空白，标签设置为

%b

，而另一个轴将有

panel.grid.minor

空白，标签设置为

%Y

。（另一个挑战是，年份标签将改为10月份，而不是1月份）

这些问题是相关的。然而，据我所知，

annotate\u custom（）

函数和

textGrob（）

函数不能很好地处理日期

数据和基本代码如下：

    library("ggplot2")
    library("scales")
    ggplot(data = df, aes(x = Date, y = value)) + geom_line() +
        scale_x_date(date_breaks = "2 month", date_minor_breaks = "1 month", labels = date_format("%b %Y")) +
        xlab(NULL)

    ggplot(data = df, aes(x = Date, y = value)) + geom_line() +
        scale_x_date(date_minor_breaks = "2 month", labels = date_format("%b")) +   
        annotate(geom = "text", x = as.Date("1719-10-01"), y = 0, label = "1719") +
        annotate(geom = "text", x = as.Date("1720-10-01"), y = 0, label = "1720") +
        xlab(NULL)


    # data
    df <- structure(list(Date = structure(c(-91455, -91454, -91453, -91452, 
    -91451, -91450, -91448, -91447, -91446, -91445, -91444, -91443, 
    -91441, -91440, -91439, -91438, -91437, -91436, -91434, -91433, 
    -91431, -91430, -91429, -91427, -91426, -91425, -91424, -91423, 
    -91422, -91420, -91419, -91418, -91417, -91416, -91415, -91413, 
    -91412, -91411, -91410, -91409, -91408, -91406, -91405, -91404, 
    -91403, -91402, -91401, -91399, -91398, -91397, -91396, -91395, 
    -91394, -91392, -91391, -91390, -91389, -91388, -91387, -91385, 
    -91384, -91382, -91381, -91380, -91379, -91377, -91376, -91375, 
    -91374, -91373, -91372, -91371, -91370, -91369, -91368, -91367, 
    -91366, -91364, -91363, -91362, -91361, -91360, -91359, -91357, 
    -91356, -91355, -91354, -91353, -91352, -91350, -91349, -91348, 
    -91347, -91346, -91345, -91343, -91342, -91341, -91340, -91339, 
    -91338, -91336, -91335, -91334, -91333, -91332, -91331, -91329, 
    -91328, -91327, -91326, -91325, -91324, -91322, -91321, -91320, 
    -91319, -91315, -91314, -91313, -91312, -91311, -91310, -91308, 
    -91307, -91306, -91305, -91304, -91303, -91301, -91300, -91299, 
    -91298, -91297, -91296, -91294, -91293, -91292, -91291, -91290, 
    -91289, -91287, -91286, -91285, -91284, -91283, -91282, -91280, 
    -91279, -91278, -91277, -91276, -91275, -91273, -91272, -91271, 
    -91270, -91269, -91268, -91266, -91265, -91264, -91263, -91262, 
    -91261, -91259, -91258, -91257, -91256, -91255, -91254, -91252, 
    -91251, -91250, -91249, -91248, -91247, -91245, -91244, -91243, 
    -91242, -91241, -91240, -91238, -91237, -91236, -91235, -91234, 
    -91233, -91231, -91230, -91229, -91228, -91227, -91226, -91224, 
    -91223, -91222, -91221, -91220, -91219, -91217, -91216, -91215, 
    -91214, -91213, -91212, -91210, -91209, -91208, -91207, -91205, 
    -91201, -91200, -91199, -91198, -91196, -91195, -91194, -91193, 
    -91192, -91191, -91189, -91188, -91187, -91186, -91185, -91184, 
    -91182, -91181, -91180, -91179, -91178, -91177, -91175, -91174, 
    -91173, -91172, -91171, -91170, -91168, -91167, -91166, -91165, 
    -91164, -91163, -91161, -91160, -91159, -91158, -91157, -91156, 
    -91154, -91153, -91152, -91151, -91150, -91149, -91147, -91146, 
    -91145, -91144, -91143, -91142, -91140, -91139, -91138, -91131, 
    -91130, -91129, -91128, -91126, -91125, -91124, -91123, -91122, 
    -91121, -91119, -91118, -91117, -91116, -91115, -91114, -91112, 
    -91111, -91110, -91109, -91108, -91107, -91104, -91103, -91102, 
    -91101, -91100, -91099, -91097, -91096, -91095, -91094, -91093, 
    -91091, -91090, -91089, -91088, -91087, -91086, -91084, -91083, 
    -91082, -91081, -91080, -91079, -91077, -91076, -91075, -91074, 
    -91073, -91072, -91070, -91069, -91068, -91065, -91063, -91062, 
    -91061, -91060, -91059, -91058, -91056, -91055, -91054, -91053, 
    -91052, -91051, -91049, -91048, -91047, -91046, -91045, -91044, 
    -91042, -91041, -91040, -91039, -91038, -91037, -91035, -91034, 
    -91033, -91032, -91031, -91030, -91028, -91027, -91026, -91025, 
    -91024, -91023, -91021, -91020, -91019, -91018, -91017, -91016, 
    -91014, -91013, -91012, -91011, -91010, -91009, -91007, -91006, 
    -91005, -91004, -91003, -91002, -91000, -90999, -90998, -90997, 
    -90996, -90995, -90993, -90992, -90991, -90990, -90989, -90988, 
    -90986, -90985, -90984, -90983, -90982), class = "Date"), value = c(113, 
    113, 113, 113, 114, 114, 114, 115, 115, 115, 116, 116, 116, 116, 
    117, 117, 117, 117, 116, 117, 116, 116, 116, 117, 117, 117, 117, 
    117, 117, 117, 116, 117, 116, 116, 116, 117, 117, 117, 117, 117, 
    117, 117, 116, 116, 117, 117, 117, 117, 117, 117, 117, 117, 117, 
    117, 117, 118, 118, 118, 118, 117, 118, 117, 117, 117, 117, 117, 
    117, 118, 116, 116, 116, 116, 116, 116, 116, 117, 117, 118, 118, 
    118, 118, 118, 119, 120, 120, 119, 119, 120, 120, 121, 121, 122, 
    124, 124, 122, 123, 124, 123, 123, 123, 123, 123, 124, 124, 126, 
    126, 126, 126, 126, 125, 125, 126, 127, 126, 126, 125, 126, 126, 
    126, 128, 128, 128, 130, 133, 131, 133, 134, 134, 134, 136, 136, 
    136, 135, 135, 135, 136, 136, 136, 136, 135, 135, 135, 135, 130, 
    129, 129, 130, 131, 136, 138, 155, 157, 161, 170, 174, 168, 165, 
    169, 171, 181, 184, 182, 179, 181, 179, 175, 177, 177, 174, 170, 
    174, 173, 178, 173, 178, 179, 182, 184, 184, 180, 181, 182, 182, 
    184, 184, 188, 195, 198, 220, 255, 275, 350, 310, 315, 320, 320, 
    316, 300, 310, 310, 320, 317, 313, 312, 310, 297, 285, 285, 286, 
    288, 315, 328, 338, 344, 345, 352, 352, 342, 335, 343, 340, 342, 
    339, 337, 336, 336, 342, 347, 352, 352, 351, 352, 352, 351, 352, 
    352, 355, 375, 400, 452, 487, 476, 475, 473, 485, 500, 530, 595, 
    720, 720, 770, 750, 770, 750, 735, 740, 745, 735, 700, 700, 750, 
    760, 755, 755, 760, 760, 765, 950, 950, 950, 875, 875, 875, 880, 
    880, 880, 900, 900, 900, 880, 880, 890, 895, 890, 880, 870, 870, 
    870, 870, 870, 860, 860, 860, 860, 850, 840, 810, 820, 810, 810, 
    805, 810, 805, 820, 815, 820, 805, 790, 800, 780, 760, 765, 750, 
    740, 820, 810, 800, 800, 775, 750, 810, 750, 740, 700, 705, 660, 
    630, 640, 595, 590, 570, 565, 535, 440, 400, 410, 400, 405, 390, 
    370, 300, 300, 180, 200, 310, 290, 260, 260, 275, 260, 270, 265, 
    255, 250, 210, 210, 200, 195, 210, 215, 240, 240, 220, 220, 220, 
    220, 210, 212, 208, 220, 210, 212, 208, 220, 215, 220, 214, 214, 
    213, 212, 210, 210, 195, 195, 160, 160, 175, 205, 210, 208, 197, 
    181, 185)), .Names = c("Date", "value"), row.names = c(NA, 393L
    ), class = "data.frame")

库（“ggplot2”）
图书馆（“天平”）
ggplot（数据=df，aes（x=日期，y=值））+geom_线（）+
比例x日期（日期间隔=“2个月”，日期间隔=“1个月”，标签=日期格式（“%b%Y”））+
xlab（空）
ggplot（数据=df，aes（x=日期，y=值））+geom_线（）+
比例x日期（日期次间隔=“2个月”，标签=日期格式（“%b”）+
注释（geom=“text”，x=截止日期（“1719-10-01”），y=0，label=“1719”）+
注释（geom=“text”，x=截止日期（“1720-10-01”），y=0，label=“1720”）+
xlab（空）
#资料
df下面的代码提供了两个添加年份标签的潜在选项

备选方案1a：镶嵌面
你可以用刻面来标记年份。例如：

library(ggplot2)
library(lubridate)

ggplot(df, aes(Date, value)) +
  geom_line() +
  scale_x_date(date_labels="%b", date_breaks="month", expand=c(0,0)) +
  facet_grid(~ year(Date), space="free_x", scales="free_x", switch="x") +
  theme_bw() +
  theme(strip.placement = "outside",
        strip.background = element_rect(fill=NA,colour="grey50"),
        panel.spacing=unit(0,"cm"))


请注意，使用这种方法，如果在一年的开始或结束时缺少日期（所谓“缺少”，我的意思是这些日期的行甚至不在数据中），那么x轴将在该年数据中的第一个/最后一个日期开始/结束，而不是从1月1日到12月31日。在这种情况下，您需要为缺少的日期添加行，并为
value
添加
NA
或插入
value
。此外，使用这种方法，在一年的12月31日和下一年的1月1日之间没有空间或直线，因此每年都有间断

选项1b：刻面+居中月份标签
以回应@AF7的评论。通过在每个标签前添加一些空格，可以使月份标签居中。但您必须根据打印到设备时打印的实际大小手动选择空间数。（可能有一种方法可以根据内部grob测量值以编程方式将标签居中，但我不确定该如何操作。）我还删除了次要的垂直网格线，并在几年之间将该线变亮

ggplot(df, aes(Date, value)) +
  geom_line() +
  scale_x_date(date_labels=paste(c(rep(" ",11), "%b"), collapse=""), 
               date_breaks="month", expand=c(0,0)) +
  facet_grid(~ year(Date), space="free_x", scales="free_x", switch="x") +
  theme_bw() +
  theme(strip.placement = "outside",
        strip.background = element_blank(),
        panel.grid.minor.x = element_blank(),
        panel.border = element_rect(colour="grey70"),
        panel.spacing=unit(0,"cm"))


选项2a：编辑x轴标签grob
这里有一个更复杂、更挑剔的方法（尽管它可能由比我更了解网格图形的结构和单位间距的人来自动实现），它避免了上面描述的刻面方法的陷阱：

library(grid)

# Fake data with an extra year added for illustration
set.seed(2)
df = data.frame(Date=seq(as.Date("1718-03-01"),as.Date("1721-09-20"), by="1 day"))
df$value = cumsum(rnorm(nrow(df)))

# The plot we'll start with
p = ggplot(df, aes(Date, value)) +
  geom_vline(xintercept=as.numeric(df$Date[yday(df$Date)==1]), colour="grey60") +
  geom_line() +
  scale_x_date(date_labels="%b", date_breaks="month", expand=c(0,0)) +
  theme_bw() +
  theme(panel.grid.minor.x = element_blank()) +
  labs(x="")


现在，我们希望在每年的6月和7月之间添加以下年份值。下面的代码通过修改x轴标签grob来实现这一点，并由@SandyMuspratt改编

# Get the grob
g <- ggplotGrob(p)

# Get the y axis
index <- which(g$layout$name == "axis-b")  # Which grob
xaxis <- g$grobs[[index]]   

# Get the ticks (labels and marks)
ticks <- xaxis$children[[2]]

# Get the labels
ticksB <- ticks$grobs[[2]]

# Edit x-axis label grob
# Find every index of Jun in the x-axis labels and add a newline and
# then a year label
junes = which(ticksB$children[[1]]$label == "Jun")
ticksB$children[[1]]$label[junes] = paste0(ticksB$children[[1]]$label[junes],
                                           "\n      ", unique(year(df$Date))) 

# Put the edited labels back into the plot
ticks$grobs[[2]] <- ticksB
xaxis$children[[2]] <- ticks
g$grobs[[index]] <- xaxis

# Draw the plot
grid.newpage()
grid.draw(g)

如果您想尝试拼凑一个子标签，可以将其转换为
grob
。我从最初的帖子中编辑了这篇文章，创建了一个添加子标签并返回
gtable
对象的函数。请注意，
子选项卡
输入的长度必须与x轴打断的长度相同：

library(grid)
library(gtable)
library(gridExtra)

add_sublabs <- function(plot, sublabs){

  gg <- ggplotGrob(plot)

  axis_num <- which(gg$layout[,"name"] == "axis-b")

  xbreaks <- gg[["grobs"]][[axis_num]][["children"]][[2]][["grobs"]][[2]][["children"]][[1]]$x
  if(length(xbreaks) != length(sublabs)) stop("Sub-labels must be the same length as the x-axis breaks")

  to_breaks <- c(as.numeric(xbreaks),1)[which(!duplicated(sublabs, fromLast = TRUE))+1]
  sublabs_x <- diff(c(0,to_breaks))
  sublabs_labels <- sublabs[!duplicated(sublabs, fromLast = TRUE)]

  tg <- tableGrob(matrix(sublabs_labels, nrow = 1))
  tg$widths = unit(sublabs_x, attr(xbreaks,"unit"))

  pos <- gg$layout[axis_num,c("t","l")]

  gg2 <- gtable_add_rows(gg, heights = sum(tg$heights)+unit(4,"mm"), pos = pos$t)
  gg3 <- gtable_add_grob(gg2, tg, t = pos$t+1, l = pos$l)

  return(gg3)
}


#Plot and sublabels
p <- ggplot(data = df, aes(x = Date, y = value)) + geom_line() +
  scale_x_date(date_breaks = "2 month", date_minor_breaks = "1 month", labels = date_format("%b")) +
  xlab(NULL)
sublabs <- c(rep("1719",2),rep("1720",6))

#Draw
grid.draw(add_sublabs(p, sublabs))

库（网格）
图书馆（gtable）
图书馆（gridExtra）
添加_sublabs避免复杂性的一种方法是改变所需的产出，以一年取代一月份

lab
函数返回给定中断的标签。出人意料的是，ggplot会将NAs传递给它，因此在函数体的第一行中，我们用某个日期替换它们——不管是哪个日期，因为ggplot随后不会使用这些值。最后，我们根据月份是一月（对应于POSIXlt组件
mon
等于0）还是一月，将日期格式化为年或缩写月

库（ggplot2）
图书馆（比例尺）
lab我遇到了这个问题，想也许我可以添加一个解决方案。通过使用一个简单的条件，我们可以在每年显示的第一个月中同时显示月份和年份。您可以使用
日期分隔符
从标签中删除一月，这仍然有效。我正在使用
lubridate
中的
month（）
和
year（）

library(tidyverse)
library(lubridate)

df %>% 
   ggplot(aes(Date, value)) +
   geom_line() +
   scale_x_date(date_breaks = "2 months", 
                labels = function(x) if_else(is.na(lag(x)) | !year(lag(x)) == year(x), 
                                             paste(month(x, label = TRUE), "\n", year(x)), 
                                             paste(month(x, label = TRUE))))

为什么不在
aes（）中使用
color=format（Date，“%Y”）
。在我看来，这比试图拼凑一个定制的x轴更干净。这比我想做的还要好！谢谢对于第一种方法，可能类似于
panel.border=element\u rect（color=“grey80”）
。使用第二种方法，改变
geom\u vline
颜色以改变线条的突出度，或者如果不想标定年份，只需完全删除
geom\u vline
语句。我发现这个x刻度有点像bi
library(ggplot2)
library(scales)

lab <- function(b) {
  b[is.na(b)] <- Sys.Date()
  format(b, ifelse(as.POSIXlt(b)$mon == 0, "%Y", "%b"))
}

ggplot(df, aes(Date, value)) + 
   geom_line() +
   scale_x_date(date_breaks = "month", labels = lab)

library(tidyverse)
library(lubridate)

df %>% 
   ggplot(aes(Date, value)) +
   geom_line() +
   scale_x_date(date_breaks = "2 months", 
                labels = function(x) if_else(is.na(lag(x)) | !year(lag(x)) == year(x), 
                                             paste(month(x, label = TRUE), "\n", year(x)), 
                                             paste(month(x, label = TRUE))))