如何交换或指定图例元素的位置？

Question

无论我如何尝试，我似乎都无法调换情节中两个图例元素的位置。

我需要 Chats started 先出现，Chats completed 接下来出现。

这是数据框：

grouped <- structure(list(date = c("2018-07-16", "2018-07-17", "2018-07-18", 
"2018-07-19", "2018-07-20", "2018-07-21", "2018-07-22", "2018-07-23", 
"2018-07-24", "2018-07-25", "2018-07-26", "2018-07-27", "2018-07-28", 
"2018-07-29", "2018-07-30", "2018-07-31"), homepage_opens = c(5L, 
0L, 0L, 3L, 1L, 2L, 0L, 1L, 0L, 2L, 5L, 0L, 0L, 0L, 0L, 0L), 
    sitewide_opens = c(39L, 34L, 19L, 62L, 46L, 44L, 16L, 51L, 
    25L, 66L, 75L, 0L, 0L, 0L, 0L, 0L), chats_started = c(10L, 
    16L, 9L, 8L, 13L, 13L, 5L, 13L, 4L, 8L, 11L, 0L, 0L, 0L, 
    0L, 0L), chats_completed = c(7L, 13L, 8L, 4L, 5L, 9L, 6L, 
    13L, 2L, 7L, 5L, 0L, 0L, 0L, 0L, 0L)), class = c("tbl_df", 
"tbl", "data.frame"), row.names = c(NA, -16L))

剧情代码如下：

library(ggplot2)

ggplot(grouped) +
  geom_col(aes(x = date, y = chats_started, fill = "Chats started"),
           colour = "black",
           alpha = 0.5) +
  geom_col(aes(x = date, y = chats_completed, fill = "Chats completed"),
           colour = "black",
           alpha = 0.5) +
  geom_text(aes(x = date, y = chats_started, label = chats_started),
            colour = "black",
            hjust = -0.15,
            vjust = -1.5,
            size = 3) +
  geom_text(aes(x = date, y = chats_completed, label = chats_completed),
            hjust = -0.15,
            vjust = -1.5,
            size = 3,
            colour = "black") +
  labs(title = paste0("Chat Analysis\n(started vs. completed)"),
       x = "Date",
       y = "Count") +
  theme(legend.position = "top",
        legend.title = element_blank(),
        panel.grid.minor.x = element_blank(),
        panel.grid.major.x = element_blank(),
        axis.text = element_text(colour = "black")) +
  scale_fill_manual(values = c("Chats completed" = "lightgreen", "Chats started" = "sandybrown"),
                    labels = c("Chats completed", "Chats started"))

这是我最终得到的结果：

Answer 1

您只需要guide = guide_legend(reverse=TRUE)，如Cookbook for R所示：

ggplot(grouped) +
    geom_col(aes(x = date, y = chats_started, fill = "Chats started"),
             colour = "black",
             alpha = 0.5) +
    geom_col(aes(x = date, y = chats_completed, fill = "Chats completed"),
             colour = "black",
             alpha = 0.5) +
    geom_text(aes(x = date, y = chats_started, label = chats_started),
              colour = "black",
              hjust = -0.15,
              vjust = -1.5,
              size = 3) +
    geom_text(aes(x = date, y = chats_completed, label = chats_completed),
              hjust = -0.15,
              vjust = -1.5,
              size = 3,
              colour = "black") +
    labs(title = paste0("Chat Analysis\n(started vs. completed)"),
         x = "Date",
         y = "Count") +
    theme(legend.position = "top",
          legend.title = element_blank(),
          panel.grid.minor.x = element_blank(),
          panel.grid.major.x = element_blank(),
          axis.text = element_text(colour = "black")) +
    scale_fill_manual(values = c("Chats completed" = "lightgreen", "Chats started" = "sandybrown"),
                      labels = c("Chats completed", "Chats started"),
                      guide = guide_legend(reverse=TRUE))

对于它的价值，搜索显示了几个与图例排序相关的不同问题以及类似问题的各种解决方案：

ggplot legends - change labels, order and title
How to reorder a legend in ggplot2?
Controlling ggplot2 legend display order

但是，none 这些问题的答案显示了针对反转图例顺序这一特定问题的简单解决方案，所以我提供了这个答案而不是尝试判断众多问题中的一个是否实际上足够接近以标记为重复。

如何交换或指定图例元素的位置？

How can I swap or specify the position of legend elements?

r

legend

geom-col