geom_bar中的条形宽度相同(position ="dodge")

Question

我想绘制具有相同宽度的条形图.这是我的最小示例代码:

data <- data.frame(A = letters[1:17],
                   B = sample(1:500, 17),
                   C = c(rep(1, 5), rep(2, 6), rep(c(3,4,5), each = 2)))

ggplot(data,
       aes(x = C,  y = B, label = A,
           fill = A)) +
  geom_bar(stat = "identity", position = "dodge") +
  geom_text(position = position_dodge(width = 0.9), angle = 90)

结果如上图所示:

条的宽度取决于变量中给出的组中的观察数C.我想让每个酒吧都有相同的宽度.

该facet_grid(~C)作品(条宽度相同)这不是我的意思:

ggplot(data,
       aes(x = C,  y = B, label = A,
           fill = A)) +
  geom_bar(stat = "identity", position = "dodge") +
  geom_text(position = position_dodge(width = 0.9), angle = 90) +
  facet_grid(~C)

我想要的是像第一张图片中的情节一样,但是条的宽度与列中每个级别的观察次数无关C.我该怎么做？

[编辑] geom_bar(width)改变了酒吧组的宽度,但第五组中的酒吧仍然比第一组更宽,所以这不是我的问题的答案.

Answer 1

更新

使用ggplot2_3.0.0版本,你现在可以使用position_dodge2与preserve = c("total", "single")

ggplot(data,aes(x = C,  y = B, label = A, fill = A)) +
  geom_col(position = position_dodge2(width = 0.9, preserve = "single")) +
  geom_text(position = position_dodge2(width = 0.9, preserve = "single"), angle = 90, vjust=0.25)

原始答案

正如已经评论过的那样,您可以像在这个答案中那样做:转换A和C使用因子并使用tidyr's 添加看不见的变量complete.自最近的ggplot2版本以来,建议使用geom_col而不是geom_bar在以下情况下stat = "identity":

data %>% 
  as.tibble() %>% 
  mutate_at(c("A", "C"), as.factor) %>% 
  complete(A,C) %>% 
  ggplot(aes(x = C,  y = B, fill = A)) +
  geom_col(position = "dodge")

或者使用交互术语:

data %>% 
  ggplot(aes(x = interaction(C, A),  y = B, fill = A)) +
  geom_col(position = "dodge")

最后通过将交互转换为数字,您可以根据所需的输出设置x轴.通过分组(group_by),您可以计算匹配的中断.{}围绕ggplot参数的花哨的东西是直接使用vaiables Breaks和C管道内的neseccary .

data %>% 
  mutate(gr=as.numeric(interaction(C, A))) %>% 
  group_by(C) %>% 
  mutate(Breaks=mean(gr)) %>% 
  {ggplot(data=.,aes(x = gr,  y = B, fill = A, label = A)) +
   geom_col(position = "dodge") +
   geom_text(position = position_dodge(width = 0.9), angle = 90 ) +
   scale_x_continuous(breaks = unique(.$Breaks),
                     labels = unique(.$C))}

编辑:

另一种方法是使用facet.使用space = "free_x"允许设置与x刻度的长度成比例的宽度.

library(tidyverse)
data %>% 
  ggplot(aes(x = A,  y = B, fill = A))  +  
   geom_col(position = "dodge") +
   facet_grid(~C, scales = "free_x", space = "free_x")

您还可以使用switch和删除x轴标签在底部绘制构面标签

data %>% 
  ggplot(aes(x = A,  y = B, fill = A))  +  
  geom_col(position = "dodge") +
  facet_grid(~C, scales = "free_x", space = "free_x", switch = "x") + 
  theme(axis.text.x = element_blank(),
        axis.ticks.x = element_blank(),
        strip.background = element_blank())