Ggplot，两边各有两个y轴和不同的刻度

这在ggplot2中是不可能的，因为我认为具有单独y尺度的图(不是相互转换的y尺度)从根本上是有缺陷的。一些问题:

• 它们是不可逆的:给定绘图空间上的一个点，你不能唯一地将它映射回数据空间中的一个点。

• 与其他选项相比，它们相对难以正确阅读。详见 a Study on double - scale Data Charts by Petra Isenberg, Anastasia Bezerianos, Pierre Dragicevic和Jean-Daniel Fekete。

• 它们很容易被操纵来误导:没有唯一的方法来指定坐标轴的相对尺度，这使得它们容易被操纵。来自Junkcharts博客的两个例子: 1 ， 2

• 它们是任意的:为什么只有2个等级，而不是3、4或10 ?

你也可能想读Stephen Few关于图形中的双尺度轴是最佳解决方案吗?这个话题的冗长讨论。

有时客户想要两个y刻度。给他们“有缺陷”的演讲通常是毫无意义的。但是我喜欢ggplot2坚持以正确的方式做事。我确信ggplot实际上是在向普通用户传授正确的可视化技术。

也许你可以使用面形和无比例来比较两个数据序列?-例如:看这里:https://github.com/hadley/ggplot2/wiki/Align-two-plots-on-a-page

下面的文章帮助我将ggplot2生成的两个图合并到单行上:

一页多图(ggplot2) by Cookbook for R

下面是代码在这种情况下的样子:

p1 <-
ggplot() + aes(mns)+ geom_histogram(aes(y=..density..), binwidth=0.01, colour="black", fill="white") + geom_vline(aes(xintercept=mean(mns, na.rm=T)), color="red", linetype="dashed", size=1) +  geom_density(alpha=.2)


p2 <-
ggplot() + aes(mns)+ geom_histogram( binwidth=0.01, colour="black", fill="white") + geom_vline(aes(xintercept=mean(mns, na.rm=T)), color="red", linetype="dashed", size=1)


multiplot(p1,p2,cols=2)

你可以在变量上使用facet_wrap(~ variable, ncol= )来创建一个新的比较。它们不在同一个轴上，但很相似。

这个挑战的解决方案的技术骨干已经由Kohske在大约3年前[KOHSKE]提供。在Stackoverflow [id: 18989001, 29235405, 21026598]的几个实例中已经讨论过这个主题及其解决方案的技术细节。因此，我将只提供一个特定的变化和一些解释性演练，使用上述解决方案。

让我们假设组G1中确实有一些数据日元，组G2中的一些数据y2以某种方式相关，例如范围/比例转换或添加了一些噪声。因此，我们希望将数据一起绘制在一个图形上，左侧为日元，右侧为y2。

  df <- data.frame(item=LETTERS[1:n],  y1=c(-0.8684, 4.2242, -0.3181, 0.5797, -0.4875), y2=c(-5.719, 205.184, 4.781, 41.952, 9.911 )) # made up!


> df
item      y1         y2
1    A -0.8684 -19.154567
2    B  4.2242 219.092499
3    C -0.3181  18.849686
4    D  0.5797  46.945161
5    E -0.4875  -4.721973

如果我们现在把数据画在一起

ggplot(data=df, aes(label=item)) +
theme_bw() +
geom_segment(aes(x='G1', xend='G2', y=y1, yend=y2), color='grey')+
geom_text(aes(x='G1', y=y1), color='blue') +
geom_text(aes(x='G2', y=y2), color='red') +
theme(legend.position='none', panel.grid=element_blank())

它不能很好地对齐，因为较小的规模日元明显被较大的规模y2所折叠。

这里迎接挑战的技巧是技术上绘制 数据集，对照第一个比例尺y1，但根据二级轴报告第二个，其中标签显示原始比例尺y2。

因此，我们构建了一个第一个辅助函数CalcFudgeAxis，它计算和收集要显示的新轴的特征。函数可以根据自己的喜好进行修改(这个函数只是将y2映射到日元的范围)。

CalcFudgeAxis = function( y1, y2=y1) {
Cast2To1 = function(x) ((ylim1[2]-ylim1[1])/(ylim2[2]-ylim2[1])*x) # x gets mapped to range of ylim2
ylim1 <- c(min(y1),max(y1))
ylim2 <- c(min(y2),max(y2))
yf <- Cast2To1(y2)
labelsyf <- pretty(y2)
return(list(
yf=yf,
labels=labelsyf,
breaks=Cast2To1(labelsyf)
))
}

什么产生了一些:

> FudgeAxis <- CalcFudgeAxis( df$y1, df$y2 )


> FudgeAxis
$yf
[1] -0.4094344  4.6831656  0.4029175  1.0034664 -0.1009335


$labels
[1] -50   0  50 100 150 200 250


$breaks
[1] -1.068764  0.000000  1.068764  2.137529  3.206293  4.275058  5.343822




> cbind(df, FudgeAxis$yf)
item      y1         y2 FudgeAxis$yf
1    A -0.8684 -19.154567   -0.4094344
2    B  4.2242 219.092499    4.6831656
3    C -0.3181  18.849686    0.4029175
4    D  0.5797  46.945161    1.0034664
5    E -0.4875  -4.721973   -0.1009335

现在，我在第二个辅助函数PlotWithFudgeAxis中包装了Kohske的解决方案(我们将新轴的ggplot对象和辅助对象放入其中):

library(gtable)
library(grid)


PlotWithFudgeAxis = function( plot1, FudgeAxis) {
# based on: https://rpubs.com/kohske/dual_axis_in_ggplot2
plot2 <- plot1 + with(FudgeAxis, scale_y_continuous( breaks=breaks, labels=labels))


#extract gtable
g1<-ggplot_gtable(ggplot_build(plot1))
g2<-ggplot_gtable(ggplot_build(plot2))


#overlap the panel of the 2nd plot on that of the 1st plot
pp<-c(subset(g1$layout, name=="panel", se=t:r))
g<-gtable_add_grob(g1, g2$grobs[[which(g2$layout$name=="panel")]], pp$t, pp$l, pp$b,pp$l)


ia <- which(g2$layout$name == "axis-l")
ga <- g2$grobs[[ia]]
ax <- ga$children[[2]]
ax$widths <- rev(ax$widths)
ax$grobs <- rev(ax$grobs)
ax$grobs[[1]]$x <- ax$grobs[[1]]$x - unit(1, "npc") + unit(0.15, "cm")
g <- gtable_add_cols(g, g2$widths[g2$layout[ia, ]$l], length(g$widths) - 1)
g <- gtable_add_grob(g, ax, pp$t, length(g$widths) - 1, pp$b)


grid.draw(g)
}

现在可以把它们放在一起:下面的代码显示了建议的解决方案如何在日常环境中使用。plot调用现在不再绘制原始数据y2，而是一个克隆版本yf(保存在预先计算的帮助对象FudgeAxis中)，其运行规模为日元。然后使用Kohske的辅助函数PlotWithFudgeAxis操作原始ggplot对象，以添加第二个轴，保留y2的刻度。它的情节和被操纵的情节一样。

FudgeAxis <- CalcFudgeAxis( df$y1, df$y2 )


tmpPlot <- ggplot(data=df, aes(label=item)) +
theme_bw() +
geom_segment(aes(x='G1', xend='G2', y=y1, yend=FudgeAxis$yf), color='grey')+
geom_text(aes(x='G1', y=y1), color='blue') +
geom_text(aes(x='G2', y=FudgeAxis$yf), color='red') +
theme(legend.position='none', panel.grid=element_blank())


PlotWithFudgeAxis(tmpPlot, FudgeAxis)

现在可以用两个轴来绘制，左边是y1，右边是y2

上面的解决方案，坦率地说，是一个有限的不稳定的hack。当它使用ggplot内核时，它将抛出一些警告，提示我们交换事后的规模，等等。它必须小心处理，并可能在另一个环境中产生一些不受欢迎的行为。此外，你可能需要摆弄辅助函数来获得所需的布局。图例的位置就是这样一个问题(它将被放置在面板和新轴之间;这就是我放弃它的原因)。两个轴的缩放/对齐也有点挑战性:当两个刻度都包含“0”时，上面的代码工作得很好，否则一个轴会被移位。所以肯定有提高的机会。

如果on想要保存图片，就必须将调用包装成设备打开/关闭:

png(...)
PlotWithFudgeAxis(tmpPlot, FudgeAxis)
dev.off()

从ggplot2 2.2.0开始，你可以像这样添加一个辅助轴(取自Ggplot2 2.2.0公告):

ggplot(mpg, aes(displ, hwy)) +
geom_point() +
scale_y_continuous(
"mpg (US)",
sec.axis = sec_axis(~ . * 1.20, name = "mpg (UK)")
)

哈德利的回答对Stephen Few的报告图形中的双尺度轴是最佳解决方案吗?给出了一个有趣的引用。

我不知道OP的“计数”和“率”是什么意思，但快速搜索给了我计数和费率，所以我得到了一些关于北美登山事故的数据__abc1:

Years<-c("1998","1999","2000","2001","2002","2003","2004")
Persons.Involved<-c(281,248,301,276,295,231,311)
Fatalities<-c(20,17,24,16,34,18,35)
rate=100*Fatalities/Persons.Involved
df<-data.frame(Years=Years,Persons.Involved=Persons.Involved,Fatalities=Fatalities,rate=rate)
print(df,row.names = FALSE)


Years Persons.Involved Fatalities      rate
1998              281         20  7.117438
1999              248         17  6.854839
2000              301         24  7.973422
2001              276         16  5.797101
2002              295         34 11.525424
2003              231         18  7.792208
2004              311         35 11.254019

然后，我尝试按照Few在上述报告第7页建议的那样绘制图表(并按照OP的要求将计数绘制为柱状图，将率绘制为折线图):

另一个不太明显的解决方案，只适用于时间序列，是 将所有值集转换为一个共同的定量刻度 显示每个值和引用之间的百分比差异 (或索引)值。例如，选择一个特定的时间点， 如在图中出现的第一个区间，并表示 值之间的百分比差 初始值。这是通过将每个点的值除以来完成的 时间乘以初始时间点的值，然后乘以 它通过100将比率转换为百分比，如下所示

df2<-df
df2$Persons.Involved <- 100*df$Persons.Involved/df$Persons.Involved[1]
df2$rate <- 100*df$rate/df$rate[1]
plot(ggplot(df2)+
geom_bar(aes(x=Years,weight=Persons.Involved))+
geom_line(aes(x=Years,y=rate,group=1))+
theme(text = element_text(size=30))
)

但我不是很喜欢它，我不能轻易地给它加上一个传奇……

对我来说，棘手的部分是计算出两个轴之间的变换函数。为此我使用了myCurveFit。

> dput(combined_80_8192 %>% filter (time > 270, time < 280))
structure(list(run = c(268L, 268L, 268L, 268L, 268L, 268L, 268L,
268L, 268L, 268L, 263L, 263L, 263L, 263L, 263L, 263L, 263L, 263L,
263L, 263L, 269L, 269L, 269L, 269L, 269L, 269L, 269L, 269L, 269L,
269L, 261L, 261L, 261L, 261L, 261L, 261L, 261L, 261L, 261L, 261L,
267L, 267L, 267L, 267L, 267L, 267L, 267L, 267L, 267L, 267L, 265L,
265L, 265L, 265L, 265L, 265L, 265L, 265L, 265L, 265L, 266L, 266L,
266L, 266L, 266L, 266L, 266L, 266L, 266L, 266L, 262L, 262L, 262L,
262L, 262L, 262L, 262L, 262L, 262L, 262L, 264L, 264L, 264L, 264L,
264L, 264L, 264L, 264L, 264L, 264L, 260L, 260L, 260L, 260L, 260L,
260L, 260L, 260L, 260L, 260L), repetition = c(8L, 8L, 8L, 8L,
8L, 8L, 8L, 8L, 8L, 8L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L, 3L,
9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 9L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 7L, 5L, 5L,
5L, 5L, 5L, 5L, 5L, 5L, 5L, 5L, 6L, 6L, 6L, 6L, 6L, 6L, 6L, 6L,
6L, 6L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 4L, 4L, 4L, 4L,
4L, 4L, 4L, 4L, 4L, 4L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L, 0L
), module = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L), .Label = "scenario.node[0].nicVLCTail.phyVLC", class = "factor"),
configname = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L,
1L, 1L), .Label = "Road-Vlc", class = "factor"), packetByteLength = c(8192L,
8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L,
8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L,
8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L,
8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L,
8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L,
8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L,
8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L,
8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L,
8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L,
8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L,
8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L, 8192L
), numVehicles = c(2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L,
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L
), dDistance = c(80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L,
80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L,
80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L,
80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L,
80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L,
80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L,
80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L,
80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L,
80L, 80L, 80L, 80L, 80L, 80L, 80L, 80L), time = c(270.166006903445,
271.173853699836, 272.175873251122, 273.177524313334, 274.182946177105,
275.188959464989, 276.189675339937, 277.198250244799, 278.204619457189,
279.212562800009, 270.164199199177, 271.168527215152, 272.173072994958,
273.179210429715, 274.184351047337, 275.18980754378, 276.194816792995,
277.198598277809, 278.202398083519, 279.210634593917, 270.210674322891,
271.212395107473, 272.218871923292, 273.219060500457, 274.220486359614,
275.22401452372, 276.229646658839, 277.231060448138, 278.240407241942,
279.2437126347, 270.283554249858, 271.293168593832, 272.298574288769,
273.304413221348, 274.306272082517, 275.309023049011, 276.317805897347,
277.324403550028, 278.332855848701, 279.334046374594, 270.118608539613,
271.127947700074, 272.133887145863, 273.135726000491, 274.135994529981,
275.136563912708, 276.140120735361, 277.144298344151, 278.146885137621,
279.147552358659, 270.206015567272, 271.214618077209, 272.216566814903,
273.225435592582, 274.234014573683, 275.242949179958, 276.248417809711,
277.248800670023, 278.249750333404, 279.252926560188, 270.217182684494,
271.218357511397, 272.224698488895, 273.231112784327, 274.238740508457,
275.242715184122, 276.249053562718, 277.250325509798, 278.258488063493,
279.261141590137, 270.282904173953, 271.284689544638, 272.294220723234,
273.299749415592, 274.30628880553, 275.312075103126, 276.31579134717,
277.321905523606, 278.326305136748, 279.333056502253, 270.258991527456,
271.260224091407, 272.270076810133, 273.27052037648, 274.274119348094,
275.280808254502, 276.286353887245, 277.287064312339, 278.294444793276,
279.296772014594, 270.333066283904, 271.33877455992, 272.345842319903,
273.350858180493, 274.353972278505, 275.360454510107, 276.365088896161,
277.369166956941, 278.372571708911, 279.38017503079), distanceToTx = c(80.255266401689,
80.156059067023, 79.98823695539, 79.826647129071, 79.76678667135,
79.788239825292, 79.734539327997, 79.74766421514, 79.801243848241,
79.765920888341, 80.255266401689, 80.15850240049, 79.98823695539,
79.826647129071, 79.76678667135, 79.788239825292, 79.735078924078,
79.74766421514, 79.801243848241, 79.764622734914, 80.251248121732,
80.146436869316, 79.984682320466, 79.82292012342, 79.761908518748,
79.796988776281, 79.736920997657, 79.745038376718, 79.802638836686,
79.770029970452, 80.243475525691, 80.127918207499, 79.978303140866,
79.816259117883, 79.749322030693, 79.809916018889, 79.744456560867,
79.738655068783, 79.788697533211, 79.784288359619, 80.260412958482,
80.168426829066, 79.992034911214, 79.830845773284, 79.7756751763,
79.778156038931, 79.732399593756, 79.752769548846, 79.799967731078,
79.757585110481, 80.251248121732, 80.146436869316, 79.984682320466,
79.822062073459, 79.75884601899, 79.801590491435, 79.738335109094,
79.74347007248, 79.803215965043, 79.771471198955, 80.250257298678,
80.146436869316, 79.983831684476, 79.822062073459, 79.75884601899,
79.801590491435, 79.738335109094, 79.74347007248, 79.803849157574,
79.771471198955, 80.243475525691, 80.130180105198, 79.978303140866,
79.816881283718, 79.749322030693, 79.80984572883, 79.744456560867,
79.738655068783, 79.790548644175, 79.784288359619, 80.246349000313,
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79.814065350562, 79.743657315504, 79.810146783217, 79.749945098869,
79.737122584544, 79.781650522348, 79.791554933936), headerNoError = c(0.99999999989702,
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0.99894450514543, 0.99890078483692, 0.76933812306423), receivedPower_dbm = c(-93.023492290586,
-92.388378035287, -92.205716340607, -93.816400586752, -95.023489422885,
-100.86308557253, -98.464763536915, -96.175707680373, -102.06189538385,
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-92.411048503835, -92.203136463155, -93.807357409082, -95.012865008237,
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-99.708301333236, -92.735781110993, -92.408137395049, -92.119533319039,
-94.982938427575, -96.181073124017, -102.03018610927, -99.721633629806,
-97.32940323644, -97.347613268692, -100.87007386786), snr = c(49.848348091678,
57.698190927109, 60.17669971462, 41.529809724535, 31.452202106925,
8.1976890851341, 14.240447804094, 24.122884195464, 6.2202875499406,
10.674183333671, 49.848348091678, 57.746270018264, 60.17669971462,
41.529809724535, 31.452202106925, 8.1976890851341, 14.242292077376,
24.122884195464, 6.2202875499406, 10.672962852322, 49.854827699773,
57.49079026127, 60.192705735317, 41.549715223147, 31.499301851462,
6.2853718719014, 13.937702343688, 24.133388256416, 6.2028757927148,
10.677815810561, 49.867624820879, 57.417115267867, 60.224172277442,
41.635752021705, 24.074540962859, 6.2847854917092, 10.644529778044,
24.19227425387, 10.537686730745, 10.699414795917, 49.84017267426,
53.139646558768, 60.160512118809, 41.509660845114, 31.42665220053,
8.1846370024428, 14.231126423354, 31.584125885363, 6.2494585568733,
10.654622041348, 49.854827699773, 57.49079026127, 60.192705735317,
41.55465351989, 31.509340361646, 6.2867464196657, 13.941251828322,
24.140336174865, 4.765718874642, 10.679016976694, 49.856439162736,
57.49079026127, 60.196678846453, 41.55465351989, 31.509340361646,
6.2867464196657, 13.941251828322, 24.140336174865, 4.7666691818074,
10.679016976694, 49.867624820879, 57.412299088098, 60.224172277442,
41.630930975211, 24.074540962859, 6.279972363168, 10.644529778044,
24.19227425387, 10.546845071479, 10.699414795917, 49.862851240855,
57.397787176282, 60.212457625018, 41.61637603957, 31.529239767749,
6.2952688513108, 10.640565481982, 24.178672145334, 8.0771089950663,
10.694731030907, 53.262541905639, 57.43627424514, 61.382796189332,
31.747253311549, 24.093100244121, 6.2658701281075, 10.661949889074,
18.495227442305, 18.417839037171, 8.1845086722809), frameId = c(15051,
15106, 15165, 15220, 15279, 15330, 15385, 15452, 15511, 15566,
15019, 15074, 15129, 15184, 15239, 15298, 15353, 15412, 15471,
15526, 14947, 14994, 15057, 15112, 15171, 15226, 15281, 15332,
15391, 15442, 14971, 15030, 15085, 15144, 15203, 15262, 15321,
15380, 15435, 15490, 14915, 14978, 15033, 15092, 15147, 15198,
15257, 15312, 15371, 15430, 14975, 15034, 15089, 15140, 15195,
15254, 15313, 15368, 15427, 15478, 14987, 15046, 15105, 15160,
15215, 15274, 15329, 15384, 15447, 15506, 14943, 15002, 15061,
15116, 15171, 15230, 15285, 15344, 15399, 15454, 14971, 15026,
15081, 15136, 15195, 15258, 15313, 15368, 15423, 15478, 15039,
15094, 15149, 15204, 15263, 15314, 15369, 15428, 15487, 15546
), packetOkSinr = c(0.99999999314881, 0.9999999998736, 0.99999999996428,
0.99999952114066, 0.99991568416005, 3.00628034688444e-08,
0.51497487795954, 0.99627877136019, 0, 0.011303253101957,
0.99999999314881, 0.99999999987726, 0.99999999996428, 0.99999952114066,
0.99991568416005, 3.00628034688444e-08, 0.51530974419663,
0.99627877136019, 0, 0.011269851265775, 0.9999999931708,
0.99999999985986, 0.99999999996428, 0.99999952599145, 0.99991770469509,
0, 0.45861812482641, 0.99629897628155, 0, 0.011403119534097,
0.99999999321568, 0.99999999985437, 0.99999999996519, 0.99999954639936,
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0.00801687746446111, 0.012011103529927, 0.9999999931195,
0.99999999871861, 0.99999999996428, 0.99999951617905, 0.99991456738049,
2.6525298291169e-08, 0.51328066587104, 0.9999212220316, 0,
0.010777054258914, 0.9999999931708, 0.99999999985986, 0.99999999996428,
0.99999952718674, 0.99991812902805, 0, 0.45929307038653,
0.99631228046814, 0, 0.011436292559188, 0.99999999317629,
0.99999999985986, 0.99999999996428, 0.99999952718674, 0.99991812902805,
0, 0.45929307038653, 0.99631228046814, 0, 0.011436292559188,
0.99999999321568, 0.99999999985437, 0.99999999996519, 0.99999954527918,
0.99618434878558, 0, 0.010513119213425, 0.99641022914441,
0.00821047996950475, 0.012011103529927, 0.99999999319919,
0.99999999985345, 0.99999999996519, 0.99999954188106, 0.99991896371849,
0, 0.010410830482692, 0.996384831822, 9.12484388049251e-09,
0.011877185067536, 0.99999999879646, 0.9999999998562, 0.99999999998077,
0.99992756868677, 0.9962208785486, 0, 0.010971897073662,
0.93214999078663, 0.92943956665979, 2.64925478221656e-08),
snir = c(49.848348091678, 57.698190927109, 60.17669971462,
41.529809724535, 31.452202106925, 8.1976890851341, 14.240447804094,
24.122884195464, 6.2202875499406, 10.674183333671, 49.848348091678,
57.746270018264, 60.17669971462, 41.529809724535, 31.452202106925,
8.1976890851341, 14.242292077376, 24.122884195464, 6.2202875499406,
10.672962852322, 49.854827699773, 57.49079026127, 60.192705735317,
41.549715223147, 31.499301851462, 6.2853718719014, 13.937702343688,
24.133388256416, 6.2028757927148, 10.677815810561, 49.867624820879,
57.417115267867, 60.224172277442, 41.635752021705, 24.074540962859,
6.2847854917092, 10.644529778044, 24.19227425387, 10.537686730745,
10.699414795917, 49.84017267426, 53.139646558768, 60.160512118809,
41.509660845114, 31.42665220053, 8.1846370024428, 14.231126423354,
31.584125885363, 6.2494585568733, 10.654622041348, 49.854827699773,
57.49079026127, 60.192705735317, 41.55465351989, 31.509340361646,
6.2867464196657, 13.941251828322, 24.140336174865, 4.765718874642,
10.679016976694, 49.856439162736, 57.49079026127, 60.196678846453,
41.55465351989, 31.509340361646, 6.2867464196657, 13.941251828322,
24.140336174865, 4.7666691818074, 10.679016976694, 49.867624820879,
57.412299088098, 60.224172277442, 41.630930975211, 24.074540962859,
6.279972363168, 10.644529778044, 24.19227425387, 10.546845071479,
10.699414795917, 49.862851240855, 57.397787176282, 60.212457625018,
41.61637603957, 31.529239767749, 6.2952688513108, 10.640565481982,
24.178672145334, 8.0771089950663, 10.694731030907, 53.262541905639,
57.43627424514, 61.382796189332, 31.747253311549, 24.093100244121,
6.2658701281075, 10.661949889074, 18.495227442305, 18.417839037171,
8.1845086722809), ookSnirBer = c(8.8808636558081e-24, 3.2219795637026e-27,
2.6468895519653e-28, 3.9807779074715e-20, 1.0849324265615e-15,
2.5705217057696e-05, 4.7313805615763e-08, 1.8800438086075e-12,
0.00021005320203921, 1.9147343768384e-06, 8.8808636558081e-24,
3.0694773489537e-27, 2.6468895519653e-28, 3.9807779074715e-20,
1.0849324265615e-15, 2.5705217057696e-05, 4.7223753038869e-08,
1.8800438086075e-12, 0.00021005320203921, 1.9171738578051e-06,
8.8229427230445e-24, 3.9715925056443e-27, 2.6045198111088e-28,
3.9014083702734e-20, 1.0342658440386e-15, 0.00019591630514278,
6.4692014108683e-08, 1.8600094209271e-12, 0.0002140067535655,
1.9074922485477e-06, 8.7096574467175e-24, 4.2779443633862e-27,
2.5231916788231e-28, 3.5761615214425e-20, 1.9750692814982e-12,
0.0001960392878411, 1.9748966344895e-06, 1.7515881895994e-12,
2.2078334799411e-06, 1.8649940680806e-06, 8.954486301678e-24,
3.2021085732779e-25, 2.690441113724e-28, 4.0627628846548e-20,
1.1134484878561e-15, 2.6061691733331e-05, 4.777159157954e-08,
9.4891388749738e-16, 0.00020359398491544, 1.9542110660398e-06,
8.8229427230445e-24, 3.9715925056443e-27, 2.6045198111088e-28,
3.8819641115984e-20, 1.0237769828158e-15, 0.00019562832342849,
6.4455095380046e-08, 1.8468752030971e-12, 0.0010099091367628,
1.9051035165106e-06, 8.8085966897635e-24, 3.9715925056443e-27,
2.594108048185e-28, 3.8819641115984e-20, 1.0237769828158e-15,
0.00019562832342849, 6.4455095380046e-08, 1.8468752030971e-12,
0.0010088638355194, 1.9051035165106e-06, 8.7096574467175e-24,
4.2987746909572e-27, 2.5231916788231e-28, 3.593647329558e-20,
1.9750692814982e-12, 0.00019705170257492, 1.9748966344895e-06,
1.7515881895994e-12, 2.1868296425817e-06, 1.8649940680806e-06,
8.7517439682173e-24, 4.3621551072316e-27, 2.553168170837e-28,
3.6469582463164e-20, 1.0032983660212e-15, 0.00019385229409318,
1.9830820164805e-06, 1.7760568361323e-12, 2.919419915209e-05,
1.8741284335866e-06, 2.8285944348148e-25, 4.1960751547207e-27,
7.8468215407139e-29, 8.0407329049747e-16, 1.9380328071065e-12,
0.00020004849911333, 1.9393279417733e-06, 5.9354475879597e-10,
6.4258355913627e-10, 2.6065221215415e-05), ookSnrBer = c(8.8808636558081e-24,
3.2219795637026e-27, 2.6468895519653e-28, 3.9807779074715e-20,
1.0849324265615e-15, 2.5705217057696e-05, 4.7313805615763e-08,
1.8800438086075e-12, 0.00021005320203921, 1.9147343768384e-06,
8.8808636558081e-24, 3.0694773489537e-27, 2.6468895519653e-28,
3.9807779074715e-20, 1.0849324265615e-15, 2.5705217057696e-05,
4.7223753038869e-08, 1.8800438086075e-12, 0.00021005320203921,
1.9171738578051e-06, 8.8229427230445e-24, 3.9715925056443e-27,
2.6045198111088e-28, 3.9014083702734e-20, 1.0342658440386e-15,
0.00019591630514278, 6.4692014108683e-08, 1.8600094209271e-12,
0.0002140067535655, 1.9074922485477e-06, 8.7096574467175e-24,
4.2779443633862e-27, 2.5231916788231e-28, 3.5761615214425e-20,
1.9750692814982e-12, 0.0001960392878411, 1.9748966344895e-06,
1.7515881895994e-12, 2.2078334799411e-06, 1.8649940680806e-06,
8.954486301678e-24, 3.2021085732779e-25, 2.690441113724e-28,
4.0627628846548e-20, 1.1134484878561e-15, 2.6061691733331e-05,
4.777159157954e-08, 9.4891388749738e-16, 0.00020359398491544,
1.9542110660398e-06, 8.8229427230445e-24, 3.9715925056443e-27,
2.6045198111088e-28, 3.8819641115984e-20, 1.0237769828158e-15,
0.00019562832342849, 6.4455095380046e-08, 1.8468752030971e-12,
0.0010099091367628, 1.9051035165106e-06, 8.8085966897635e-24,
3.9715925056443e-27, 2.594108048185e-28, 3.8819641115984e-20,
1.0237769828158e-15, 0.00019562832342849, 6.4455095380046e-08,
1.8468752030971e-12, 0.0010088638355194, 1.9051035165106e-06,
8.7096574467175e-24, 4.2987746909572e-27, 2.5231916788231e-28,
3.593647329558e-20, 1.9750692814982e-12, 0.00019705170257492,
1.9748966344895e-06, 1.7515881895994e-12, 2.1868296425817e-06,
1.8649940680806e-06, 8.7517439682173e-24, 4.3621551072316e-27,
2.553168170837e-28, 3.6469582463164e-20, 1.0032983660212e-15,
0.00019385229409318, 1.9830820164805e-06, 1.7760568361323e-12,
2.919419915209e-05, 1.8741284335866e-06, 2.8285944348148e-25,
4.1960751547207e-27, 7.8468215407139e-29, 8.0407329049747e-16,
1.9380328071065e-12, 0.00020004849911333, 1.9393279417733e-06,
5.9354475879597e-10, 6.4258355913627e-10, 2.6065221215415e-05
)), class = "data.frame", row.names = c(NA, -100L), .Names = c("run",
"repetition", "module", "configname", "packetByteLength", "numVehicles",
"dDistance", "time", "distanceToTx", "headerNoError", "receivedPower_dbm",
"snr", "frameId", "packetOkSinr", "snir", "ookSnirBer", "ookSnrBer"
))

求变换函数

1. y1—> y2 该函数用于将次要y轴的数据按照第一个y轴
进行“归一化”

变换函数:f(y1) = 0.025*x + 2.75

2. y2—> y1 该函数用于将第一个y轴的断点转换为第二个y轴的值。注意，现在坐标轴被交换了

变换函数:f(y1) = 40*x - 110

策划

注意如何在ggplot调用中使用转换函数来“动态”转换数据

ggplot(data=combined_80_8192 %>% filter (time > 270, time < 280), aes(x=time) ) +
stat_summary(aes(y=receivedPower_dbm ), fun.y=mean, geom="line", colour="black") +
stat_summary(aes(y=packetOkSinr*40 - 110 ), fun.y=mean, geom="line", colour="black", position = position_dodge(width=10)) +
scale_x_continuous() +
scale_y_continuous(breaks = seq(-0,-110,-10), "y_first", sec.axis=sec_axis(~.*0.025+2.75, name="y_second") )

现在要转换第二个轴，我在scale_y_continuous调用中使用相反的函数:sec.axis=sec_axis(~.*0.025+2.75, name="y_second")。

我们肯定可以使用基本R函数plot来构建一个具有双y轴的plot。

# pseudo dataset
df <- data.frame(x = seq(1, 1000, 1), y1 = sample.int(100, 1000, replace=T), y2 = sample(50, 1000, replace = T))


# plot first plot
with(df, plot(y1 ~ x, col = "red"))


# set new plot
par(new = T)


# plot second plot, but without axis
with(df, plot(y2 ~ x, type = "l", xaxt = "n", yaxt = "n", xlab = "", ylab = ""))


# define y-axis and put y-labs
axis(4)
with(df, mtext("y2", side = 4))

我承认并同意哈德利(和其他人)的观点，单独的y量表是“有根本缺陷的”。话虽如此——我经常希望ggplot2有这个功能——特别是当数据在宽格式中，我很快就想可视化或检查数据(即仅供个人使用)。

虽然tidyverse库使得将数据转换为长格式相当容易(这样facet_grid()就可以工作)，但这个过程仍然不是简单的，如下所示:

library(tidyverse)
df.wide %>%
# Select only the columns you need for the plot.
select(date, column1, column2, column3) %>%
# Create an id column – needed in the `gather()` function.
mutate(id = n()) %>%
# The `gather()` function converts to long-format.
# In which the `type` column will contain three factors (column1, column2, column3),
# and the `value` column will contain the respective values.
# All the while we retain the `id` and `date` columns.
gather(type, value, -id, -date) %>%
# Create the plot according to your specifications
ggplot(aes(x = date, y = value)) +
geom_line() +
# Create a panel for each `type` (ie. column1, column2, column3).
# If the types have different scales, you can use the `scales="free"` option.
facet_grid(type~., scales = "free")

根据上面的答案和一些微调(无论它是值得的)，下面是一种通过sec_axis实现两个尺度的方法:

假设有一个简单的(完全虚构的)数据集dt:连续五天，它跟踪中断的次数VS工作效率:

        when numinter prod
1 2018-03-20        1 0.95
2 2018-03-21        5 0.50
3 2018-03-23        4 0.70
4 2018-03-24        3 0.75
5 2018-03-25        4 0.60

(两列的范围相差大约5倍)。

下面的代码将画出它们占用整个y轴的两个级数:

ggplot() +
geom_bar(mapping = aes(x = dt$when, y = dt$numinter), stat = "identity", fill = "grey") +
geom_line(mapping = aes(x = dt$when, y = dt$prod*5), size = 2, color = "blue") +
scale_x_date(name = "Day", labels = NULL) +
scale_y_continuous(name = "Interruptions/day",
sec.axis = sec_axis(~./5, name = "Productivity % of best",
labels = function(b) { paste0(round(b * 100, 0), "%")})) +
theme(
axis.title.y = element_text(color = "grey"),
axis.title.y.right = element_text(color = "blue"))

下面是结果(上面的代码+一些颜色调整):

重点(除了在指定y_scale时使用sec_axis之外)是在指定系列时将第二个数据系列的每个值乘为5。为了在sec_axis定义中获得正确的标签，它需要分 by 5(和格式化)。因此，上述代码中的关键部分实际上是geom_line中的*5和sec_axis中的~./5(将当前值.除以5的公式)。

相比之下(我不想在这里判断方法)，这是两个图表叠加在一起的样子:

你可以自己判断哪一个能更好地传递信息(“不要打扰别人工作!”)。我想这是一个公平的决定方式。

这两个图像的完整代码(实际上并没有比上面的更多，只是完成并准备运行)在这里:https://gist.github.com/sebastianrothbucher/de847063f32fdff02c83b75f59c36a7d，更详细的解释在这里:https://sebastianrothbucher.github.io/datascience/r/visualization/ggplot/2018/03/24/two-scales-ggplot-r.html

您可以创建一个缩放因子，应用于第二个geom和右y轴。这是从塞巴斯蒂安的解推导出来的。

library(ggplot2)


scaleFactor <- max(mtcars$cyl) / max(mtcars$hp)


ggplot(mtcars, aes(x=disp)) +
geom_smooth(aes(y=cyl), method="loess", col="blue") +
geom_smooth(aes(y=hp * scaleFactor), method="loess", col="red") +
scale_y_continuous(name="cyl", sec.axis=sec_axis(~./scaleFactor, name="hp")) +
theme(
axis.title.y.left=element_text(color="blue"),
axis.text.y.left=element_text(color="blue"),
axis.title.y.right=element_text(color="red"),
axis.text.y.right=element_text(color="red")
)

注意:使用ggplot2 v3.0.0

常见的用例有双y轴，例如，气候图显示每月的温度和降水。这里是一个简单的解决方案，从威震天的解决方案中推广，允许你设置变量的下限为零:

示例数据:

climate <- tibble(
Month = 1:12,
Temp = c(-4,-4,0,5,11,15,16,15,11,6,1,-3),
Precip = c(49,36,47,41,53,65,81,89,90,84,73,55)
)

将以下两个值设置为接近数据限制的值(您可以使用这些值来调整图形的位置;坐标轴仍然是正确的):

ylim.prim <- c(0, 180)   # in this example, precipitation
ylim.sec <- c(-4, 18)    # in this example, temperature

下面根据这些极限进行必要的计算，并制作出图本身:

b <- diff(ylim.prim)/diff(ylim.sec)
a <- ylim.prim[1] - b*ylim.sec[1]) # there was a bug here


ggplot(climate, aes(Month, Precip)) +
geom_col() +
geom_line(aes(y = a + Temp*b), color = "red") +
scale_y_continuous("Precipitation", sec.axis = sec_axis(~ (. - a)/b, name = "Temperature")) +
scale_x_continuous("Month", breaks = 1:12) +
ggtitle("Climatogram for Oslo (1961-1990)")

如果你想确保红线对应于右边的y轴，你可以在代码中添加theme语句:

ggplot(climate, aes(Month, Precip)) +
geom_col() +
geom_line(aes(y = a + Temp*b), color = "red") +
scale_y_continuous("Precipitation", sec.axis = sec_axis(~ (. - a)/b, name = "Temperature")) +
scale_x_continuous("Month", breaks = 1:12) +
theme(axis.line.y.right = element_line(color = "red"),
axis.ticks.y.right = element_line(color = "red"),
axis.text.y.right = element_text(color = "red"),
axis.title.y.right = element_text(color = "red")
) +
ggtitle("Climatogram for Oslo (1961-1990)")

右轴的颜色:

我发现这个回答对我帮助最大，但发现有一些边缘情况，它似乎不能正确处理，特别是负的情况，以及我的极限有0距离的情况(如果我们从最大/最小数据中抓取极限，就会发生这种情况)。测试似乎表明，这是一致的

我使用以下代码。这里我假设我们有[x1,x2]我们想把它变换成[y1,y2]。我处理这个问题的方法是将[x1,x2]转换为[0,1](一个足够简单的转换)，然后[0,1]转换为[y1,y2]。

climate <- tibble(
Month = 1:12,
Temp = c(-4,-4,0,5,11,15,16,15,11,6,1,-3),
Precip = c(49,36,47,41,53,65,81,89,90,84,73,55)
)
#Set the limits of each axis manually:


ylim.prim <- c(0, 180)   # in this example, precipitation
ylim.sec <- c(-4, 18)    # in this example, temperature






b <- diff(ylim.sec)/diff(ylim.prim)


#If all values are the same this messes up the transformation, so we need to modify it here
if(b==0){
ylim.sec <- c(ylim.sec[1]-1, ylim.sec[2]+1)
b <- diff(ylim.sec)/diff(ylim.prim)
}
if (is.na(b)){
ylim.prim <- c(ylim.prim[1]-1, ylim.prim[2]+1)
b <- diff(ylim.sec)/diff(ylim.prim)
}




ggplot(climate, aes(Month, Precip)) +
geom_col() +
geom_line(aes(y = ylim.prim[1]+(Temp-ylim.sec[1])/b), color = "red") +
scale_y_continuous("Precipitation", sec.axis = sec_axis(~((.-ylim.prim[1]) *b  + ylim.sec[1]), name = "Temperature"), limits = ylim.prim) +
scale_x_continuous("Month", breaks = 1:12) +
ggtitle("Climatogram for Oslo (1961-1990)")

这里的关键部分是，我们用~((.-ylim.prim[1]) *b + ylim.sec[1])变换辅助y轴，然后对实际值y = ylim.prim[1]+(Temp-ylim.sec[1])/b)应用逆。我们还应该确保limits = ylim.prim。

下面包含了Dag Hjermann的基本数据和编程，改进了user4786271的策略，以创建一个“转换函数”;来优化组合绘图和数据轴，并响应浸信会的注释，这样的函数可以在R中创建。

#Climatogram for Oslo (1961-1990)
climate <- tibble(
Month = 1:12,
Temp = c(-4,-4,0,5,11,15,16,15,11,6,1,-3),
Precip = c(49,36,47,41,53,65,81,89,90,84,73,55))


#y1 identifies the position, relative to the y1 axis,
#the locations of the minimum and maximum of the y2 graph.
#Usually this will be the min and max of y1.
#y1<-(c(max(climate$Precip), 0))
#y1<-(c(150, 55))
y1<-(c(max(climate$Precip), min(climate$Precip)))


#y2 is the Minimum and maximum of the secondary axis data.
y2<-(c(max(climate$Temp), min(climate$Temp)))


#axis combines y1 and y2 into a dataframe used for regressions.
axis<-cbind(y1,y2)
axis<-data.frame(axis)


#Regression of Temperature to Precipitation:
T2P<-lm(formula = y1 ~ y2, data = axis)
T2P_summary <- summary(lm(formula = y1 ~ y2, data = axis))
T2P_summary


#Identifies the intercept and slope of regressing Temperature to Precipitation:
T2PInt<-T2P_summary$coefficients[1, 1]
T2PSlope<-T2P_summary$coefficients[2, 1]




#Regression of Precipitation to Temperature:
P2T<-lm(formula = y2 ~ y1, data = axis)
P2T_summary <- summary(lm(formula = y2 ~ y1, data = axis))
P2T_summary


#Identifies the intercept and slope of regressing Precipitation to Temperature:
P2TInt<-P2T_summary$coefficients[1, 1]
P2TSlope<-P2T_summary$coefficients[2, 1]




#Create Plot:
ggplot(climate, aes(Month, Precip)) +
geom_col() +
geom_line(aes(y = T2PSlope*Temp + T2PInt), color = "red") +
scale_y_continuous("Precipitation", sec.axis = sec_axis(~.*P2TSlope + P2TInt, name = "Temperature")) +
scale_x_continuous("Month", breaks = 1:12) +
theme(axis.line.y.right = element_line(color = "red"),
axis.ticks.y.right = element_line(color = "red"),
axis.text.y.right = element_text(color = "red"),
axis.title.y.right = element_text(color = "red")) +
ggtitle("Climatogram for Oslo (1961-1990)")

使最大值和最小值匹配可能是最合适的;但是，这种方法的另一个好处是，如果需要，可以通过更改与主轴数据相关的编程行轻松地移动与次要轴相关的绘图。下面的输出只是将y1编程行中的最小降水量输入更改为“0”，从而将最小温度水平与“0”对齐。降水的水平。

-(c(max(climate$ precp)， min(climate$ precp))))

到:y1<-(c(max(climate$ precp)， 0))

请注意，生成的新回归和ggplot2如何自动调整图形和轴，以正确地将最低温度与新的“基数”对齐。的& 0"降水的水平。同样，可以很容易地提升Temperature图，使其更加明显。下面的图是通过简单地将上面提到的线更改为:

“y1< (c(150年,55岁)),

上面的线条表示温度图的最大值与“;150";降水水平，与最低气温线重合的“55”;降水的水平。再次注意，ggplot2和由此产生的新的回归输出如何使图保持与轴的正确对齐。

以上可能不是一个理想的输出;然而，这是一个例子，说明了如何容易地操纵图形，并且在图和轴之间仍然有正确的关系。 Dag Hjermann的主题的合并提高了与plot对应的轴的识别

这是我对如何做二次轴变换的两种看法。首先，您希望将主数据和辅助数据的范围耦合起来。这通常是混乱的，因为您不想要的变量污染了全局环境。

为了更简单，我们将创建一个产生两个函数的函数工厂，其中scales::rescale()完成所有繁重的工作。因为这些是闭包，所以它们知道创建它们的环境，所以它们“有”在创建之前生成的to和from参数的“内存”。

• 一个函数进行正向转换:将辅助数据转换为主要尺度。
• 第二个函数进行反向转换:将主要单位中的数据转换为次要单位。

library(ggplot2)
library(scales)


# Function factory for secondary axis transforms
train_sec <- function(primary, secondary, na.rm = TRUE) {
# Thanks Henry Holm for including the na.rm argument!
from <- range(secondary, na.rm = na.rm)
to   <- range(primary, na.rm = na.rm)
# Forward transform for the data
forward <- function(x) {
rescale(x, from = from, to = to)
}
# Reverse transform for the secondary axis
reverse <- function(x) {
rescale(x, from = to, to = from)
}
list(fwd = forward, rev = reverse)
}

这看起来相当复杂，但是创建函数工厂会使其余的一切变得更简单。现在，在绘制图形之前，我们将通过向工厂显示主要和次要数据来生成相关函数。我们将使用经济学数据集，该数据集的unemploy和psavert列的范围非常不同。

sec <- with(economics, train_sec(unemploy, psavert))

然后我们使用y = sec$fwd(psavert)将辅助数据重新缩放到主轴，并指定~ sec$rev(.)作为辅助轴的转换参数。这给了我们一个主要范围和次要范围在图上占据相同空间的图。

ggplot(economics, aes(date)) +
geom_line(aes(y = unemploy), colour = "blue") +
geom_line(aes(y = sec$fwd(psavert)), colour = "red") +
scale_y_continuous(sec.axis = sec_axis(~sec$rev(.), name = "psavert"))

< img src = " https://i.imgur.com/hkjCQX8.png " alt = " / >

工厂比这稍微灵活一些，因为如果您只是想重新调整最大值，您可以传入下限为0的数据。

# Rescaling the maximum
sec <- with(economics, train_sec(c(0, max(unemploy)),
c(0, max(psavert))))


ggplot(economics, aes(date)) +
geom_line(aes(y = unemploy), colour = "blue") +
geom_line(aes(y = sec$fwd(psavert)), colour = "red") +
scale_y_continuous(sec.axis = sec_axis(~sec$rev(.), name = "psavert"))

< img src = " https://i.imgur.com/i9SLv5v.png " alt = " / >

^{由reprex包 (v0.3.0)创建于2021-02-05}

我承认这个例子中的区别不是很明显，但如果你仔细观察，你会发现最大值是相同的，红线比蓝色的线低。

编辑:

这个方法现在已经在ggh4x包中的help_secondary()函数中被捕获和扩展。声明:我是ggh4x的作者。

总有办法的。

这里有一个解决方案，允许完全任意轴而不重新缩放。其思想是生成两个除了轴以外完全相同的图，并使用cowplot包中的insert_yaxis_grob和get_y_axis函数将它们拼接在一起。

library(ggplot2)
library(cowplot)


## first plot
p1 <- ggplot(mtcars,aes(disp,hp,color=as.factor(am))) +
geom_point() + theme_bw() + theme(legend.position='top', text=element_text(size=16)) +
ylab("Horse points" )+ xlab("Display size") + scale_color_discrete(name='Transmitter') +
stat_smooth(se=F)


## same plot with different, arbitrary scale
p2 <- p1 +
scale_y_continuous(position='right',breaks=seq(120,173,length.out = 3),
labels=c('little','medium little','medium hefty'))


ggdraw(insert_yaxis_grob(p1,get_y_axis(p2,position='right')))