使用 ggplot2 显示图例时出现问题，没有显示...图例项在 df 中没有对应的变量答案

【问题标题】：Issue displaying legend with ggplot2, nothing displaying ... legend items have no correspnsing variable in df使用 ggplot2 显示图例时出现问题，没有显示...图例项在 df 中没有对应的变量
【发布时间】：2018-09-21 19:54:33
【问题描述】：

我正在使用 ggplot 绘制一系列线条并在它们之间进行着色。有 10 条线，但只有 5 个阴影区域。我想要 5 个阴影区域的图例。目前还没有传说。我以为这条线

scale_color_manual(name="test",labels = c("90%","70%","50%","30%","10%"), 
                 values = c("Darkolivegreen1", "Darkolivegreen2","Darkolivegreen3","Darkolivegreen4","Darkolivegreen"))

将添加带有阴影区域的手动颜色条，但没有显示。完整的情节代码如下。谢谢

Exposure_by_Month_10perc=Exposure_by_Month[,c(1,seq(3,length(monthQuant[1,])+1,4))]
dfm <- melt(Exposure_by_Month_10perc, id.vars = "Date")
dfm$value=dfm$value/1000000
colnames(dfm)=c("Date","Confidence Interval","value")

ggplot(Exposure_by_Month_10perc, aes(x=Date, y = dfm[dfm$`Confidence Interval`== "0.05",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.05",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.15",3])) + 
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.25",3])) + 
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.35",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.45",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.55",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.65",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.75",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.85",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.95",3])) +
  geom_ribbon(aes(ymin = dfm[dfm$`Confidence Interval`== "0.95",3], ymax = dfm[dfm$`Confidence Interval`== "0.05",3]), fill = "Darkolivegreen1", alpha = .5) +
  geom_ribbon(aes(ymin = dfm[dfm$`Confidence Interval`== "0.85",3], ymax = dfm[dfm$`Confidence Interval`== "0.15",3]), fill = "Darkolivegreen2", alpha = .5) +
  geom_ribbon(aes(ymin = dfm[dfm$`Confidence Interval`== "0.75",3], ymax = dfm[dfm$`Confidence Interval`== "0.25",3]), fill = "Darkolivegreen3", alpha = .5) +
  geom_ribbon(aes(ymin = dfm[dfm$`Confidence Interval`== "0.65",3], ymax = dfm[dfm$`Confidence Interval`== "0.35",3]), fill = "Darkolivegreen4", alpha = .5) +
  geom_ribbon(aes(ymin = dfm[dfm$`Confidence Interval`== "0.55",3], ymax = dfm[dfm$`Confidence Interval`== "0.45",3]), fill = "Darkolivegreen", alpha = .5) +
  scale_x_date(labels = date_format("%b-%Y"),breaks='2 months') +
  theme_bw() +
  theme(axis.text.x = element_text(angle = 45, hjust = 1)) +
  labs(title = "XXXX TITLE", subtitle = "XXX SUBTITLE") +
  xlab("Month") +
  ylab("Value, $M") +
  scale_y_continuous(label=dollar_format(),breaks = round(seq(min(dfm$value), max(dfm$value), by = 1),0)) +
  geom_line(aes(y = 0*dfm[dfm$`Confidence Interval`== "0.95",3]),linetype = "dashed") +
  scale_color_manual(name="test",labels = c("90%","70%","50%","30%","10%"), 
                     values = c("Darkolivegreen1", "Darkolivegreen2","Darkolivegreen3","Darkolivegreen4","Darkolivegreen"))
  ###why no legend

> head(Exposure_by_Month_10perc)
# A tibble: 6 x 11
  Date         `0.05`   `0.15`   `0.25`   `0.35`   `0.45`   `0.55`   `0.65`   `0.75`   `0.85`   `0.95`
  <date>        <dbl>    <dbl>    <dbl>    <dbl>    <dbl>    <dbl>    <dbl>    <dbl>    <dbl>    <dbl>
1 2018-10-01  -1.44e6  -2.58e6  -3.42e6  -4.27e6  -5.15e6  -6.01e6  -7.01e6  -8.11e6  -9.51e6  -1.21e7
2 2018-11-01  -5.36e4  -1.42e6  -2.35e6  -3.35e6  -4.40e6  -5.67e6  -7.09e6  -8.66e6  -1.07e7  -1.50e7
3 2018-12-01   6.63e5  -7.65e5  -1.87e6  -3.05e6  -4.32e6  -5.82e6  -7.62e6  -9.68e6  -1.25e7  -1.87e7
4 2019-01-01   8.34e5  -9.67e5  -1.90e6  -2.68e6  -3.64e6  -4.73e6  -5.59e6  -6.94e6  -8.66e6  -1.19e7
5 2019-02-01   1.16e6  -4.70e5  -1.52e6  -2.13e6  -3.10e6  -4.15e6  -5.13e6  -6.53e6  -8.31e6  -1.20e7
6 2019-03-01   1.88e6  -6.02e3  -1.40e6  -2.10e6  -3.26e6  -4.49e6  -5.72e6  -7.46e6  -9.74e6  -1.38e7

[没有图例的情节]1

【问题讨论】：

您可以发布Exposure_by_Month 数据框或其中的一部分吗？
已添加到帖子中。谢谢
Add legend to ggplot2 line plot的可能重复
问题是你的数据是宽格式的，而ggplot 被设计用来处理长格式的数据。看看在链接的问题中，数据是如何被重塑的，所以他们在aes 中使用了一个与color=variable 一起使用的geom_line 语句，而不是两个单独的geom_line 语句。
您希望这样，而不是每个geom_ribbon 一个变量，所有数据都在一个变量中，另一个变量区分每个区间。您需要使用 tidyr::gather 或 reshape2::melt 或类似的东西将您的数据重塑为长格式

标签： r ggplot2 legend

【解决方案1】：

试试这个：

scale_color_manual(guide="legend", labels = c("90%","70%","50%","30%","10%"), 
                 values = c("Darkolivegreen1", "Darkolivegreen2","Darkolivegreen3","Darkolivegreen4","Darkolivegreen"))

【讨论】：

谢谢，但那没有用.. 现在要对数据帧的 sn-p 提出质疑

【解决方案2】：

通过将 fill=XXX 放在 geom_ribbon 函数的 aes 括号内解决了这个问题，如下代码所示：

ggplot(Exposure_by_Month_10perc, aes(x=Date, y = dfm[dfm$`Confidence Interval`== "0.05",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.05",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.15",3])) + 
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.25",3])) + 
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.35",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.45",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.55",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.65",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.75",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.85",3])) +
  geom_line(aes(y = dfm[dfm$`Confidence Interval`== "0.95",3])) +
  geom_ribbon(aes(ymin = dfm[dfm$`Confidence Interval`== "0.95",3], ymax = dfm[dfm$`Confidence Interval`== "0.05",3], fill = "Darkolivegreen1"), alpha = .5) +
  geom_ribbon(aes(ymin = dfm[dfm$`Confidence Interval`== "0.85",3], ymax = dfm[dfm$`Confidence Interval`== "0.15",3], fill = "Darkolivegreen2"), alpha = .5) +
  geom_ribbon(aes(ymin = dfm[dfm$`Confidence Interval`== "0.75",3], ymax = dfm[dfm$`Confidence Interval`== "0.25",3], fill = "Darkolivegreen3"), alpha = .5) +
  geom_ribbon(aes(ymin = dfm[dfm$`Confidence Interval`== "0.65",3], ymax = dfm[dfm$`Confidence Interval`== "0.35",3], fill = "Darkolivegreen4"), alpha = .5) +
  geom_ribbon(aes(ymin = dfm[dfm$`Confidence Interval`== "0.55",3], ymax = dfm[dfm$`Confidence Interval`== "0.45",3], fill = "Darkolivegreen"), alpha = .5) +
  scale_x_date(labels = date_format("%b-%Y"),breaks='2 months') +
  theme_bw() +
  theme(axis.text.x = element_text(angle = 45, hjust = 1)) +
  labs(title = "Tullow Hedging Portfolio", subtitle = "Value at Risk (VAR) Analysis") +
  xlab("Month") +
  ylab("Value at Risk, $M") +
  scale_y_continuous(label=dollar_format(),breaks = round(seq(min(dfm$value), max(dfm$value), by = 1),0)) +
  geom_line(aes(y = 0*dfm[dfm$`Confidence Interval`== "0.95",3]),linetype = "dashed") +
  scale_fill_manual(name="Confidence Interval",labels = c("90%","70%","50%","30%","10%"), 
                     values = c("Darkolivegreen1", "Darkolivegreen2","Darkolivegreen3","Darkolivegreen4","Darkolivegreen"))

【讨论】：