R - ggplot 线条颜色(使用 geom_line)不会改变 [英] R - ggplot line color (using geom_line) doesn't change

问题描述

当使用 ggplot(geom_line) 在一个图上绘制 2 条线时，线的颜色与我设置的颜色不符.我想要黑色和蓝色的线条，但结果是红色和蓝色.我在没有(第一个代码)和(第二个)'scale_color_manual'的情况下尝试了它，还尝试了颜色插入，结果相同:

When ploting 2 lines on one plot with ggplot(geom_line) the color of the line doesn't compre to the color that I set. I want the lines black and blue, but the outcome is red and blue. I tried it without (first code) and with (second) 'scale_color_manual', also tried with colour insted of color, with the same result:

第一个代码:

  ggplot(data=main_data) +
  # black plot
  geom_line(aes(x=vectors_growth_rate_with_predator, 
                y=disease_prevalnce_with_predator,
                color = "black")) + 
  # blue plot
  geom_line(aes(x=vectors_growth_rate_with_predator, 
                y=disease_prevalnce_without_predator,
                color = "blue"))

第二个代码:

PrevVSGrowth = 
  ggplot(data=main_data) +
  # black plot
  geom_line(aes(x=vectors_growth_rate_with_predator, 
                y=disease_prevalnce_with_predator)) + 
  # blue plot
  geom_line(aes(x=vectors_growth_rate_with_predator, 
                y=disease_prevalnce_without_predator))

PrevVSGrowth + scale_color_manual(values=c(disease_prevalnce_with_predator= 'black',
                                           disease_prevalnce_without_predator = 'blue'))

推荐答案

你的第一个代码应该是

ggplot(data=main_data) +
# black plot
geom_line(aes(x=vectors_growth_rate_with_predator, 
              y=disease_prevalnce_with_predator),
          color = "black") + 
# blue plot
geom_line(aes(x=vectors_growth_rate_with_predator, 
              y=disease_prevalnce_without_predator),
          color = "blue")

你需要把color放在aes()之外.

对于您的第二个代码，您需要从宽到长格式.您可以通过多种方式做到这一点，以下应该适合您.

For your second code you need to reshape your data from wide to long format. You can do this in many ways, the following should work for you.

library(tidyverse)
main_data <- main_data %>% 
               gather(key, value, c("disease_prevalnce_with_predator",
                                    "disease_prevalnce_without_predator")
PrevVSGrowth <- ggplot(data=main_data) +
 geom_line(aes(x=vectors_growth_rate_with_predator, 
               y=value,
               col = key))

PrevVSGrowth + 
scale_color_manual(values = c(disease_prevalnce_with_predator= 'black',
                              disease_prevalnce_without_predator = 'blue'))

---

在第一个图中，我们在每次调用 geom_line() 时设置一个固定值的审美.这将创建两个仅包含值black"的新变量；分别为蓝色"和蓝色".在 OP 的示例中，值黑色"是和蓝色"然后缩放为红色和浅蓝色并添加图例.

---

In the first plot we set an aesthetic to a fixed value, in each call to geom_line(). This creates two new variables containing only the value "black" and "blue", respectively. In OP's example the values "black" and "blue" are then scaled to red and lightblue and a legend is added.

在第二个图中，我们映射颜色美学到一个变量(在这个例子中是key).这通常是首选方式.

In the second plot we map the colour aesthetic to a variable (key in this example). This is usually the preferred way.

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