颜色在情节中神秘地洗牌答案

【问题标题】：Colors mysteriously shuffled in the plot颜色在情节中神秘地洗牌
【发布时间】：2020-06-25 15:35:25
【问题描述】：

在 R 中使用以下 ggplot2 代码：

require(ggplot2)
df <- data.frame(x = rep(c(0, 1, 1.58,2, 2.58, 3, 3.32, 3.58, 4.17, 4.58, 5.58, 6.17, 6.5, 7.0),4), y = c(0.15,0.17,0.07,0.17,0.01,0.15,0.18,0.04,-0.06,-0.08,0,0.03,-0.27,-0.93,0.04,0.12,0.08,0.15,0.04,0.15,0.03,0.09,0.11,0.13,-0.11,-0.32,-0.7,-0.78,0.07,0.04,0.06,0.12,-0.15,0.05,-0.08,0.14,-0.02,-0.14,-0.24,-0.32,-0.78,-0.81,-0.04,-0.25,-0.09,0.02,-0.13,-0.2,-0.04,0,0.02,-0.05,-0.19,-0.37,-0.57,-0.81))
ggplot(df, aes(x = x, y = y)) + geom_point() + 
   stat_smooth(method = "lm", formula = y ~ x, size = 1, se = FALSE, aes(color = "black")) + 
   stat_smooth(method = "lm", formula = y ~ poly(x, 2), size = 1, se = FALSE, aes(color = "green")) + 
   stat_smooth(method = "lm", formula = y ~ poly(x, 3), size = 1, se = FALSE, aes(color = "orange")) + 
   stat_smooth(method = "gam", formula = y ~ s(x), size = 1, se = FALSE, aes(color = "blue")) +
   theme(legend.justification=c(1,1),legend.position=c(0.45,0.45),legend.title=element_blank()) +
   scale_color_manual(values=c("black","green","orange","blue"), labels=c("linear","quadratic","cubic","smooth"))

传说很好；但由于某种原因，四条曲线中的三条没有按预期着色：橙色曲线应为绿色，蓝色曲线应为橙色，绿色曲线应为蓝色。我错过了什么？

【问题讨论】：

为颜色传递一个命名向量以获得正确的顺序（如values = c("black" = "black", ...) 或尝试scale_color_identity() 和guide = "legend" （因为身份比例默认为无指导）。我有一个例子这在一篇博文中here。

标签： r ggplot2 colors

【解决方案1】：

你在审美调用中使用的字符串是任意的（即使你在颜色之后调用它们）。它们将在 ggplot 内部转换为因子列，并且因子的水平按字母顺序确定。因子水平被映射到scale_color_manual 调用中的值向量按照它们的放置顺序。

因此，您可以将“a”到“d”用作任意字符串，以实现颜色美学来跟踪它们并控制它们的顺序：

ggplot(df, aes(x = x, y = y)) + 
  geom_point() + 
   stat_smooth(method = "lm", formula = y ~ x, 
               size = 1, se = FALSE, aes(color = "a")) + 
   stat_smooth(method = "lm", formula = y ~ poly(x, 2), 
               size = 1, se = FALSE, aes(color = "b")) + 
   stat_smooth(method = "lm", formula = y ~ poly(x, 3), 
               size = 1, se = FALSE, aes(color = "c")) + 
   stat_smooth(method = "gam", formula = y ~ s(x), 
               size = 1, se = FALSE, aes(color = "d")) +
   theme(legend.justification = c(1, 1),
         legend.position      = c(0.45, 0.45),
         legend.title         = element_blank()) +
   scale_color_manual(values = c("black", "green", "orange", "blue"),
                      labels = c("linear", "quadratic", "cubic", "smooth"))

【讨论】：

【解决方案2】：

来自在线帮助（我的重点）：

价值观
一组美学值来映射数据值。这些值将按顺序（通常按字母顺序）与比例的限制相匹配，或者如果提供了中断。如果这是一个命名向量，则将根据名称匹配值。不匹配的数据值将被赋予 na.value。

所以试试

values=c("linear"="black","quadratic"="green","cubic"="orange","smooth"="blue")

或类似的东西。我无法检查我的代码，因为您没有提供输入数据。

【讨论】：