我正在尝试根据我设置的 y 轴的颜色在 ggplot 中创建一个图例。
有谁知道是否有一种方法可以根据图中本身不存在的数据手动创建图例?
下面是情节和代码的玩具示例。在这个图中,我绘制了 3 个不同日期的学生成绩图。学生的姓名根据他们所在的班级进行着色。我想知道我是否可以添加一个额外的图例,以绿色显示“A 班”,以紫色显示“B 班”。
作为补充说明,我意识到日子不顺。我现在并不担心这一点。
谢谢!
library(tidyverse)
name <- c("Mike", "Mike","Mike",
"Sam","Sam","Sam",
"Max","Max","Max",
"Sarah","Sarah","Sarah")
date <- c("Monday", "Wednesday", "Friday",
"Monday", "Wednesday", "Friday",
"Monday", "Wednesday", "Friday",
"Monday", "Wednesday", "Friday")
grade <- c(100, 98, 93,
92, 64, 90,
80, 88,70,
90,94,100)
classroom <- c("Class A", "Class A","Class A",
"Class A", "Class A","Class A",
"Class B", "Class B","Class B",
"Class B", "Class B","Class B")
df <- data.frame(cbind(name, date, grade, classroom)) %>%
mutate(grade = as.integer(grade),
classroom = as.factor(classroom))
plot <- ggplot(df, aes(y=name, x=date, fill= grade < 90)) +
geom_tile() +
scale_fill_manual(name = " ", values = c( "turquoise3","lightgrey"), labels = c("Above 90","At or below 90" )) +
theme(axis.text.y = element_text(color = ifelse(levels(df$classroom) %in% "Class A", "Green", "Purple"))) +
guides(size = "none", color = "none", alpha = "none")