ggplot中的热图，每组不同的颜色

Question

我正在尝试在 ggplot 中生成热图。我希望每个组都有不同的颜色渐变，但不知道该怎么做。我当前的代码如下所示：

## dummy data -----------------------------------------------------------------------------
data <- data.frame(
  group = sample(c("Direct Patient Care", "Indirect Patient Care", "Education", "Rounds", "Handoff", "Misce"), 30, replace = T),
  pct = rnorm(30, mean = 50, sd = 8)
)

## generate group id 
data <- data %>%
  group_by(group) %>%
  mutate(id = row_number())

data$grpid <- with(data, ifelse(group == "Direct Patient Care", 1, ifelse(group == "Indirect Patient Care", 2,
                                                                        ifelse(group == "Education", 3, 
                                                                               ifelse(group == "Rounds", 4,
                                                                                      ifelse(group == "Handoff", 5,6 ))))))

## draw graph ------------------------------------------------------------------------------                                                                                                                                                                           
library(ggplot2)

p <- ggplot(data, aes(x=id, y=group, fill = pct)) +
  theme(panel.background = element_rect(fill = "white", colour = "grey50"), aspect.ratio = 0.4) +
  theme(panel.grid.major = element_blank(),  
        panel.grid.minor = element_blank()
  )+
  # guides(fill = guide_legend("Time, %")) +
  geom_tile() +
  scale_x_continuous (name = " ", breaks = seq(1, 8, by = 1)) +
  scale_y_discrete(name = " ") +
  theme(axis.text.x = element_text(angle = 0,hjust = 1,vjust = 1), plot.title = element_text(hjust = 0.5) ) +
  ggtitle("Heatmap of time spent doing activities across 194 shifts")


p + scale_fill_gradient2(low = "white", high = "red", limits = c(0, 80), breaks = c(0, 10, 20, 30, 40, 50, 60, 70), guide = guide_legend("Time, %"))  ## change the color theme ##

结果图如下所示：

如何更改每个组的颜色主题，例如“轮次”为红色，“杂项”为蓝色，“Handoff”为绿色等...

非常感谢！

Answer 1

您可以通过在数据中创建自己的重新缩放值，然后稍微“修改”alpha美学与美学相结合来做到这一点fill：

library(tidyverse)

data %>%
  group_by(group) %>%
  mutate(rescale = scales::rescale(pct)) %>%
  ggplot(., aes(x = factor(id), y = group)) +
  geom_tile(aes(alpha = rescale, fill = group), color = "white") +
  scale_alpha(range = c(0.1, 1))

首先，我们创建一个名为新列rescale，其rescales在pct从0到1，那么你逼scale_alpha(range = c(0, 1))[注，在这种情况下，我使用的c(0.1, 1)，这样你仍然可以“看”到零点。

最后，您可能想要删除指南：

data %>%
  group_by(group) %>%
  mutate(rescale = scales::rescale(pct)) %>%
  ggplot(., aes(x = factor(id), y = group)) +
  geom_tile(aes(alpha = rescale, fill = group), color = "white") +
  scale_alpha(range = c(0.1, 1)) +
  theme(legend.position = "none")

注意，通过使用aes(x = factor(id)...您可以绕过手动设置，x-axis因为在这种情况下，您似乎希望将其视为一个因素而不是数字标度。

最后，如果你真的想要花哨，你可以将axis.text.y颜色双重编码为你的factor（即，data$group）变量的级别：

data %>%
  group_by(group) %>%
  mutate(rescale = scales::rescale(pct)) %>%
  ggplot(., aes(x = factor(id), y = group)) +
  geom_tile(aes(alpha = rescale, fill = group), color = "white") +
  scale_alpha(range = c(0.1, 1)) +
  theme(legend.position = "none",
        axis.text.y = element_text(color = scales::hue_pal()(length(levels(data$group)))),
        axis.ticks = element_blank()) +
  labs(x = "", y = "")