R 和 ggplot : shade the color of the categorical variable

Question

我想制作一个图表来表示一周中每一天每小时发生事件的频率。如何更改星期几的颜色？我想从黑色切换到红色以接近周末

  weekday_hour_pickup <- my_data %>%
      mutate(hour_pick = hour(new_pickup))%>%
      group_by(hour_pick, weekday) %>%
      count() %>%
      ggplot(aes(hour_pick, n, color = weekday)) +
      geom_line(size = 1.5) +
      labs(x = "hour of the day", y = "count")

  plot(weekday_hour_pickup)

Answer 1

这是一个很好的选择，可以让你的描述值看起来好像有一个渐变

# call libraries
library(dplyr)
library(ggplot2)

# define weekdays
weekdays <- c("Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", "Sunday")

# define 7 colours from black to red
colours  <- scales::seq_gradient_pal(low = "#000000", high = "#ff0000", space = "Lab")(1:7/7)

# create values for scale colour manual
values <- setNames(colours, weekdays)

# create fake data
data <- tibble(hour_pick = rep(1:24, 7), 
               n         = rnorm(7*24) + rep(1:7, each = 24), 

               # weekday must be a factor if you want your legend to be sorted!
               weekday   = factor(rep(weekdays, each = 24), levels = weekdays, ordered = TRUE))

ggplot(data) +
  geom_line(aes(x = hour_pick, y = n, colour = weekday)) +
  theme_light() +
  scale_colour_manual(values = values)