r - ggplot : re-order categorical y-axis (Gantt chart)

Question

我正在尝试从具有不同任务(每个任务都有开始日期和结束日期)的表格中生成甘特图。

library(tidyverse)

# Sample data
df1 <- data.frame(from = c("2020-01-01", "2020-02-02", "2020-05-04", "2020-02-01", "2020-01-20", "2020-02-10"),
                  to =   c("2020-03-30", "2020-03-15", "2020-05-20", "2020-04-05", "2020-03-05", "2020-04-13"),
                  task= c("Task 1", "Task 2", "Task 3", "Task 4", "Task 5", "Task 6"),
                  group = c("Finance", "Finance", "Research", "Research", "Other", "Other")
)

# Plot gantt-chart
df1 %>% mutate(from = as.Date(from),
               to = as.Date(to)) %>% 
  pivot_longer(cols = c(from, to), values_to = "date") %>%
  ggplot(aes(x=date, y=task, colour = group)) + 
  geom_line(lwd=3) +
  geom_point(aes(color=group), alpha=.5, pch=18, size=5) +
  scale_x_date(position="bottom", date_breaks = "1 week", date_labels="%U") +
  theme_bw() +
  theme(plot.title = element_text(hjust = 0.5))+
  ggtitle("Milestones") +
  labs(y="", x = "", colour="Responsible")

到目前为止一切顺利，但现在我遇到了一个主要问题和一个小问题:

主要问题:

• 如何重新排列 y 轴上的类别，因为它们出现在数据中(不是按字母顺序排列)？从上到下应该是:财务、研究、其他。此外，在每个类别(金融、研究、其他)中，行应按开始日期排序(即首先开始的任务应在最前面)

小问题:

• 如何在 x 轴上为每个月画一条粗线，为每周画一条细线？

感谢您的帮助!

Answer 1

这可以这样实现:

1. 正如@RuiBarrades 在他的评论中提到的那样，要获得正确的顺序，您必须转换为一个因子并以正确的顺序设置级别。首先，为组设置级别。其次，为了按所需顺序获取任务，我按组和开始日期重新排列数据集，并使用 forcats::fct_inorder 以所需顺序设置任务级别。

2. 如果我没看错，您想要每周和每月使用不同的网格线吗？这可以通过设置 date_breaks_minor="month" 和通过 theme 和 panel.grid.minor/major.x 设置网格线样式来实现.在这里，我选择了“黑色”颜色，但如果您喜欢不同的尺寸，可以通过 size 进行选择。

library(tidyverse)
library(ggplot2)

# Sample data
df1 <- data.frame(from = c("2020-01-01", "2020-02-02", "2020-05-04", "2020-02-01", "2020-01-20", "2020-02-10"),
                  to =   c("2020-03-30", "2020-03-15", "2020-05-20", "2020-04-05", "2020-03-05", "2020-04-13"),
                  task= c("Task 1", "Task 2", "Task 3", "Task 4", "Task 5", "Task 6"),
                  group = c("Finance", "Finance", "Research", "Research", "Other", "Other")
)

# Plot gantt-chart
df1 %>% mutate(from = as.Date(from),
               to = as.Date(to),
               group = factor(group, levels = c("Finance", "Research", "Other"))) %>%
  arrange(desc(group), desc(from)) %>% 
  mutate(task = forcats::fct_inorder(task)) %>% 
  pivot_longer(cols = c(from, to), values_to = "date") %>%
  ggplot(aes(x=date, y=task, colour = group)) + 
  geom_line(lwd=3) +
  geom_point(aes(color=group), alpha=.5, pch=18, size=5) +
  scale_x_date(position="bottom", date_breaks = "1 week", date_minor_breaks = "1 month",
               date_labels="%U") +
  theme_bw() +
  theme(plot.title = element_text(hjust = 0.5), 
        panel.grid.minor.x = element_line(color = "black"))+
  ggtitle("Milestones") +
  labs(y="", x = "", colour="Responsible")